<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:01a068fb-eb6f-751c-9fa4-08559d9a15c7,g:878fae96-4666-41e8-86c2-ea2c4585c445-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/BALANCESHEETSUNAUDITED" xlink:type="simple" xlink:href="sps-20260930.xsd#BALANCESHEETSUNAUDITED"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/BALANCESHEETSUNAUDITED" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_01a068fb-ec13-7025-86bb-bf9409a62b4a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_01a068fb-ec13-70c2-9c9b-2bb8c291dc59" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_01a068fb-ec13-7025-86bb-bf9409a62b4a" xlink:to="loc_us-gaap_StatementTable_01a068fb-ec13-70c2-9c9b-2bb8c291dc59" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ec13-72cc-b3dd-365a957111b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_01a068fb-ec13-70c2-9c9b-2bb8c291dc59" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ec13-72cc-b3dd-365a957111b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-72cc-b3dd-365a957111b5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ec13-72cc-b3dd-365a957111b5" xlink:to="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-72cc-b3dd-365a957111b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-7ed5-8293-79f59940ea3a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ec13-72cc-b3dd-365a957111b5" xlink:to="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-7ed5-8293-79f59940ea3a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_01a068fb-ec13-7327-a5c0-35ccebf8ca81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-7ed5-8293-79f59940ea3a" xlink:to="loc_us-gaap_NonrelatedPartyMember_01a068fb-ec13-7327-a5c0-35ccebf8ca81" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_01a068fb-ec13-7f8e-aac8-0a2caa087af4" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-7ed5-8293-79f59940ea3a" xlink:to="loc_srt_AffiliatedEntityMember_01a068fb-ec13-7f8e-aac8-0a2caa087af4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_01a068fb-ec13-73ea-9920-236f95307366" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-7ed5-8293-79f59940ea3a" xlink:to="loc_us-gaap_RelatedPartyMember_01a068fb-ec13-73ea-9920-236f95307366" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_01a068fb-ec13-7f25-b9ff-231a5c315a26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a068fb-ec13-7025-86bb-bf9409a62b4a" xlink:to="loc_us-gaap_AssetsAbstract_01a068fb-ec13-7f25-b9ff-231a5c315a26" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_01a068fb-ec13-781d-84b8-e4fb1ad0c916" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a068fb-ec13-7f25-b9ff-231a5c315a26" xlink:to="loc_us-gaap_AssetsCurrentAbstract_01a068fb-ec13-781d-84b8-e4fb1ad0c916" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_01a068fb-ec13-7e44-8a35-bbc8c12ce522" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_01a068fb-ec13-781d-84b8-e4fb1ad0c916" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_01a068fb-ec13-7e44-8a35-bbc8c12ce522" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_01a068fb-ec13-7dbd-8c8a-2620aa7bfc00" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_01a068fb-ec13-781d-84b8-e4fb1ad0c916" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_01a068fb-ec13-7dbd-8c8a-2620aa7bfc00" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_AccruedUnbilledRevenues_01a068fb-ec13-74ce-b31c-c3f61f334934" xlink:href="sps-20260930.xsd#sps_AccruedUnbilledRevenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_01a068fb-ec13-781d-84b8-e4fb1ad0c916" xlink:to="loc_sps_AccruedUnbilledRevenues_01a068fb-ec13-74ce-b31c-c3f61f334934" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesInventory_01a068fb-ec13-789f-b5d6-f7d77b3556a4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesInventory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_01a068fb-ec13-781d-84b8-e4fb1ad0c916" xlink:to="loc_us-gaap_PublicUtilitiesInventory_01a068fb-ec13-789f-b5d6-f7d77b3556a4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsCurrent_01a068fb-ec13-73fb-9848-3ab113fc748c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_01a068fb-ec13-781d-84b8-e4fb1ad0c916" xlink:to="loc_us-gaap_RegulatoryAssetsCurrent_01a068fb-ec13-73fb-9848-3ab113fc748c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedges_01a068fb-ec13-7423-9c7c-9388f8d9b5a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsAndHedges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_01a068fb-ec13-781d-84b8-e4fb1ad0c916" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedges_01a068fb-ec13-7423-9c7c-9388f8d9b5a1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_01a068fb-ec13-7600-a8ce-d7da250b9b8c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_01a068fb-ec13-781d-84b8-e4fb1ad0c916" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_01a068fb-ec13-7600-a8ce-d7da250b9b8c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_01a068fb-ec13-7311-9664-9bce5e7ca1b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_01a068fb-ec13-781d-84b8-e4fb1ad0c916" xlink:to="loc_us-gaap_AssetsCurrent_01a068fb-ec13-7311-9664-9bce5e7ca1b7" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_01a068fb-ec13-70d1-b906-ef939cc3956a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a068fb-ec13-7f25-b9ff-231a5c315a26" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_01a068fb-ec13-70d1-b906-ef939cc3956a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsNoncurrentAbstract_01a068fb-ec13-791d-ac2a-f98e3aca8ef3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a068fb-ec13-7f25-b9ff-231a5c315a26" xlink:to="loc_us-gaap_AssetsNoncurrentAbstract_01a068fb-ec13-791d-ac2a-f98e3aca8ef3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsNoncurrent_01a068fb-ec13-7919-9288-322ada5056dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_01a068fb-ec13-791d-ac2a-f98e3aca8ef3" xlink:to="loc_us-gaap_RegulatoryAssetsNoncurrent_01a068fb-ec13-7919-9288-322ada5056dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_01a068fb-ec13-7a87-a575-65681f3cdffa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_01a068fb-ec13-791d-ac2a-f98e3aca8ef3" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_01a068fb-ec13-7a87-a575-65681f3cdffa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_01a068fb-ec13-7c4e-9d48-68adff00390b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_01a068fb-ec13-791d-ac2a-f98e3aca8ef3" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_01a068fb-ec13-7c4e-9d48-68adff00390b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_OtherAssetsExcludingPropertyPlantAndEquipment_01a068fb-ec13-7a7e-bf73-a07101a475da" xlink:href="sps-20260930.xsd#sps_OtherAssetsExcludingPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_01a068fb-ec13-791d-ac2a-f98e3aca8ef3" xlink:to="loc_sps_OtherAssetsExcludingPropertyPlantAndEquipment_01a068fb-ec13-7a7e-bf73-a07101a475da" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_01a068fb-ec13-7d33-add7-8bd34ccf03bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a068fb-ec13-7f25-b9ff-231a5c315a26" xlink:to="loc_us-gaap_Assets_01a068fb-ec13-7d33-add7-8bd34ccf03bb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a068fb-ec13-7c3d-ba84-0ad6f3d0a1eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a068fb-ec13-7025-86bb-bf9409a62b4a" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a068fb-ec13-7c3d-ba84-0ad6f3d0a1eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_01a068fb-ec13-75dd-a6cf-819993b466c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a068fb-ec13-7c3d-ba84-0ad6f3d0a1eb" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_01a068fb-ec13-75dd-a6cf-819993b466c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_01a068fb-ec13-7c00-95d8-1e1941d06cec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_01a068fb-ec13-75dd-a6cf-819993b466c9" xlink:to="loc_us-gaap_ShortTermBorrowings_01a068fb-ec13-7c00-95d8-1e1941d06cec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_BorrowingsPayableUnderUtilityMoneyPoolArrangement_01a068fb-ec13-7fce-9c8b-09b6c781e49f" xlink:href="sps-20260930.xsd#sps_BorrowingsPayableUnderUtilityMoneyPoolArrangement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_01a068fb-ec13-75dd-a6cf-819993b466c9" xlink:to="loc_sps_BorrowingsPayableUnderUtilityMoneyPoolArrangement_01a068fb-ec13-7fce-9c8b-09b6c781e49f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_01a068fb-ec13-72f1-8974-cbf2161db6c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_01a068fb-ec13-75dd-a6cf-819993b466c9" xlink:to="loc_us-gaap_AccountsPayableCurrent_01a068fb-ec13-72f1-8974-cbf2161db6c2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityCurrent_01a068fb-ec13-7d4f-96fe-db655ec69748" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_01a068fb-ec13-75dd-a6cf-819993b466c9" xlink:to="loc_us-gaap_RegulatoryLiabilityCurrent_01a068fb-ec13-7d4f-96fe-db655ec69748" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxesPayableCurrent_01a068fb-ec13-7534-b266-e3693a9cd857" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxesPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_01a068fb-ec13-75dd-a6cf-819993b466c9" xlink:to="loc_us-gaap_TaxesPayableCurrent_01a068fb-ec13-7534-b266-e3693a9cd857" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPayableCurrent_01a068fb-ec13-7530-b681-4e68a08d56d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_01a068fb-ec13-75dd-a6cf-819993b466c9" xlink:to="loc_us-gaap_InterestPayableCurrent_01a068fb-ec13-7530-b681-4e68a08d56d6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableCurrent_01a068fb-ec13-746d-8f2a-41940e79235b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_01a068fb-ec13-75dd-a6cf-819993b466c9" xlink:to="loc_us-gaap_DividendsPayableCurrent_01a068fb-ec13-746d-8f2a-41940e79235b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_01a068fb-ec13-7534-8531-bd550d8562ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_01a068fb-ec13-75dd-a6cf-819993b466c9" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_01a068fb-ec13-7534-8531-bd550d8562ee" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_01a068fb-ec13-745c-960c-a43b62d87f9f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_01a068fb-ec13-75dd-a6cf-819993b466c9" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_01a068fb-ec13-745c-960c-a43b62d87f9f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_01a068fb-ec13-7015-ae56-283c9710e2a3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_01a068fb-ec13-75dd-a6cf-819993b466c9" xlink:to="loc_us-gaap_LiabilitiesCurrent_01a068fb-ec13-7015-ae56-283c9710e2a3" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesOtherThanLongTermDebtNoncurrentAbstract_01a068fb-ec13-7a65-b305-878aaf1e76b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesOtherThanLongTermDebtNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a068fb-ec13-7c3d-ba84-0ad6f3d0a1eb" xlink:to="loc_us-gaap_LiabilitiesOtherThanLongTermDebtNoncurrentAbstract_01a068fb-ec13-7a65-b305-878aaf1e76b2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_01a068fb-ec13-71ec-9926-d4da2dfb6489" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesOtherThanLongTermDebtNoncurrentAbstract_01a068fb-ec13-7a65-b305-878aaf1e76b2" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_01a068fb-ec13-71ec-9926-d4da2dfb6489" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityNoncurrent_01a068fb-ec13-7179-a121-ced41b1964c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RegulatoryLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesOtherThanLongTermDebtNoncurrentAbstract_01a068fb-ec13-7a65-b305-878aaf1e76b2" xlink:to="loc_us-gaap_RegulatoryLiabilityNoncurrent_01a068fb-ec13-7179-a121-ced41b1964c4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetRetirementObligationsNoncurrent_01a068fb-ec13-7c25-a0af-25d82039fce7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetRetirementObligationsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesOtherThanLongTermDebtNoncurrentAbstract_01a068fb-ec13-7a65-b305-878aaf1e76b2" xlink:to="loc_us-gaap_AssetRetirementObligationsNoncurrent_01a068fb-ec13-7c25-a0af-25d82039fce7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_01a068fb-ec13-7f84-9340-364dfa3e3c7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesOtherThanLongTermDebtNoncurrentAbstract_01a068fb-ec13-7a65-b305-878aaf1e76b2" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_01a068fb-ec13-7f84-9340-364dfa3e3c7b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_01a068fb-ec13-786d-905c-cfc86a9a1670" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesOtherThanLongTermDebtNoncurrentAbstract_01a068fb-ec13-7a65-b305-878aaf1e76b2" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_01a068fb-ec13-786d-905c-cfc86a9a1670" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_01a068fb-ec13-7a66-b51a-1614a1f9084f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesOtherThanLongTermDebtNoncurrentAbstract_01a068fb-ec13-7a65-b305-878aaf1e76b2" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_01a068fb-ec13-7a66-b51a-1614a1f9084f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesOtherThanLongtermDebtNoncurrent_01a068fb-ec13-74af-9aa5-d5cc37e22fa1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesOtherThanLongtermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesOtherThanLongTermDebtNoncurrentAbstract_01a068fb-ec13-7a65-b305-878aaf1e76b2" xlink:to="loc_us-gaap_LiabilitiesOtherThanLongtermDebtNoncurrent_01a068fb-ec13-74af-9aa5-d5cc37e22fa1" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizationLongtermDebtAndEquityAbstract_01a068fb-ec13-7b4f-b1c0-8b824c681cfc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizationLongtermDebtAndEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a068fb-ec13-7c3d-ba84-0ad6f3d0a1eb" xlink:to="loc_us-gaap_CapitalizationLongtermDebtAndEquityAbstract_01a068fb-ec13-7b4f-b1c0-8b824c681cfc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_01a068fb-ec13-7b54-bc94-f05260c80d68" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquityAbstract_01a068fb-ec13-7b4f-b1c0-8b824c681cfc" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_01a068fb-ec13-7b54-bc94-f05260c80d68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_01a068fb-ec13-7c24-bf97-09a32c1f8e68" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquityAbstract_01a068fb-ec13-7b4f-b1c0-8b824c681cfc" xlink:to="loc_us-gaap_CommonStockValue_01a068fb-ec13-7c24-bf97-09a32c1f8e68" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_01a068fb-ec13-7c7d-a9f7-56cee57e9bfb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquityAbstract_01a068fb-ec13-7b4f-b1c0-8b824c681cfc" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_01a068fb-ec13-7c7d-a9f7-56cee57e9bfb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_01a068fb-ec13-7eaf-b93e-497cc177109f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquityAbstract_01a068fb-ec13-7b4f-b1c0-8b824c681cfc" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_01a068fb-ec13-7eaf-b93e-497cc177109f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_01a068fb-ec13-7f4e-9e5b-3acd70961a9f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquityAbstract_01a068fb-ec13-7b4f-b1c0-8b824c681cfc" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_01a068fb-ec13-7f4e-9e5b-3acd70961a9f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_CommonStockSharesIssuedNotDisclosed_01a068fb-ec13-7ca9-9afd-af152178d48d" xlink:href="sps-20260930.xsd#sps_CommonStockSharesIssuedNotDisclosed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquityAbstract_01a068fb-ec13-7b4f-b1c0-8b824c681cfc" xlink:to="loc_sps_CommonStockSharesIssuedNotDisclosed_01a068fb-ec13-7ca9-9afd-af152178d48d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_01a068fb-ec13-78c2-b10a-0a8fd07d6090" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquityAbstract_01a068fb-ec13-7b4f-b1c0-8b824c681cfc" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_01a068fb-ec13-78c2-b10a-0a8fd07d6090" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_01a068fb-ec13-7c05-93fd-6930fece354d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquityAbstract_01a068fb-ec13-7b4f-b1c0-8b824c681cfc" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_01a068fb-ec13-7c05-93fd-6930fece354d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_01a068fb-ec13-7157-a100-519809e0a5b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquityAbstract_01a068fb-ec13-7b4f-b1c0-8b824c681cfc" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_01a068fb-ec13-7157-a100-519809e0a5b8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_01a068fb-ec13-7103-aca4-ae7763c2e16c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizationLongtermDebtAndEquityAbstract_01a068fb-ec13-7b4f-b1c0-8b824c681cfc" xlink:to="loc_us-gaap_StockholdersEquity_01a068fb-ec13-7103-aca4-ae7763c2e16c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_01a068fb-ec13-776f-9735-eb0de3fcc88a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a068fb-ec13-7c3d-ba84-0ad6f3d0a1eb" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_01a068fb-ec13-776f-9735-eb0de3fcc88a" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/CONSOLIDATEDSTATEMENTSOFCOMMONSTOCKHOLDERSEQUITYUNAUDITED" xlink:type="simple" xlink:href="sps-20260930.xsd#CONSOLIDATEDSTATEMENTSOFCOMMONSTOCKHOLDERSEQUITYUNAUDITED"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/CONSOLIDATEDSTATEMENTSOFCOMMONSTOCKHOLDERSEQUITYUNAUDITED" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_01a068fb-ec13-78ed-8a65-fcaeb92de6be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_01a068fb-ec13-7ba4-a454-bbf58fd34afb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_01a068fb-ec13-78ed-8a65-fcaeb92de6be" xlink:to="loc_us-gaap_StatementTable_01a068fb-ec13-7ba4-a454-bbf58fd34afb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_01a068fb-ec13-74d6-a376-1a290f43ae7f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_01a068fb-ec13-7ba4-a454-bbf58fd34afb" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_01a068fb-ec13-74d6-a376-1a290f43ae7f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_01a068fb-ec13-74d6-a376-1a290f43ae7f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_01a068fb-ec13-74d6-a376-1a290f43ae7f" xlink:to="loc_us-gaap_EquityComponentDomain_01a068fb-ec13-74d6-a376-1a290f43ae7f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_01a068fb-ec13-7042-b337-dc0160979bbf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_01a068fb-ec13-74d6-a376-1a290f43ae7f" xlink:to="loc_us-gaap_EquityComponentDomain_01a068fb-ec13-7042-b337-dc0160979bbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_01a068fb-ec13-78d6-b2e4-360d59e0aeee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a068fb-ec13-7042-b337-dc0160979bbf" xlink:to="loc_us-gaap_CommonStockMember_01a068fb-ec13-78d6-b2e4-360d59e0aeee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_01a068fb-ec13-7d0e-a2ec-3de28c5e91c3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a068fb-ec13-7042-b337-dc0160979bbf" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_01a068fb-ec13-7d0e-a2ec-3de28c5e91c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_01a068fb-ec13-7c3d-a506-0bed2611d42a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a068fb-ec13-7042-b337-dc0160979bbf" xlink:to="loc_us-gaap_RetainedEarningsMember_01a068fb-ec13-7c3d-a506-0bed2611d42a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_01a068fb-ec13-7f0b-b680-75dac026d4f0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a068fb-ec13-7042-b337-dc0160979bbf" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_01a068fb-ec13-7f0b-b680-75dac026d4f0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a068fb-ec13-7b72-92bf-3917415bd4b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a068fb-ec13-78ed-8a65-fcaeb92de6be" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a068fb-ec13-7b72-92bf-3917415bd4b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_01a068fb-ec13-78d0-a0d0-e92b24a8e4d9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a068fb-ec13-7b72-92bf-3917415bd4b8" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_01a068fb-ec13-78d0-a0d0-e92b24a8e4d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_01a068fb-ec13-7fac-bf9b-3dfc5bd24b8e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a068fb-ec13-7b72-92bf-3917415bd4b8" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_01a068fb-ec13-7fac-bf9b-3dfc5bd24b8e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_01a068fb-ec13-771d-85a0-d95b4e49501a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a068fb-ec13-7b72-92bf-3917415bd4b8" xlink:to="loc_us-gaap_NetIncomeLoss_01a068fb-ec13-771d-85a0-d95b4e49501a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStock_01a068fb-ec13-79fb-9d72-a0e795740e28" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a068fb-ec13-7b72-92bf-3917415bd4b8" xlink:to="loc_us-gaap_DividendsCommonStock_01a068fb-ec13-79fb-9d72-a0e795740e28" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalOther_01a068fb-ec13-7f2c-8d8f-edf0325ee138" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a068fb-ec13-7b72-92bf-3917415bd4b8" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalOther_01a068fb-ec13-7f2c-8d8f-edf0325ee138" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_01a068fb-ec13-7ced-b087-57a97400553e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_01a068fb-ec13-71ef-aac0-f85c72e5c6df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/BorrowingsandOtherFinancingInstrumentsTables" xlink:type="simple" xlink:href="sps-20260930.xsd#BorrowingsandOtherFinancingInstrumentsTables"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/BorrowingsandOtherFinancingInstrumentsTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7578-b629-eb50c580bfd9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShortTermDebtTable_01a068fb-ec13-7250-9ec0-5da7dc1da683" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShortTermDebtTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7578-b629-eb50c580bfd9" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTable_01a068fb-ec13-7250-9ec0-5da7dc1da683" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-7a03-a4fd-8858174a57e7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_01a068fb-ec13-7250-9ec0-5da7dc1da683" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-7a03-a4fd-8858174a57e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7a03-a4fd-8858174a57e7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-7a03-a4fd-8858174a57e7" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7a03-a4fd-8858174a57e7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7f7a-ad92-9a000ecde3eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-7a03-a4fd-8858174a57e7" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7f7a-ad92-9a000ecde3eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_MoneyPoolMember_01a068fb-ec13-70d8-9440-bcaee56f3abf" xlink:href="sps-20260930.xsd#sps_MoneyPoolMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7f7a-ad92-9a000ecde3eb" xlink:to="loc_sps_MoneyPoolMember_01a068fb-ec13-70d8-9440-bcaee56f3abf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_01a068fb-ec13-705d-908f-3da9d2efbf68" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7f7a-ad92-9a000ecde3eb" xlink:to="loc_us-gaap_CommercialPaperMember_01a068fb-ec13-705d-908f-3da9d2efbf68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentsAbstract_01a068fb-ec13-793f-9a38-160bba2b7342" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7578-b629-eb50c580bfd9" xlink:to="loc_us-gaap_DebtInstrumentsAbstract_01a068fb-ec13-793f-9a38-160bba2b7342" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShortTermDebtTextBlock_01a068fb-ec13-7bac-a6ee-9f0732b58c81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShortTermDebtTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentsAbstract_01a068fb-ec13-793f-9a38-160bba2b7342" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTextBlock_01a068fb-ec13-7bac-a6ee-9f0732b58c81" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfLineOfCreditFacilitiesTextBlock_01a068fb-ec13-7a19-a23c-dd5d460ab49b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfLineOfCreditFacilitiesTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentsAbstract_01a068fb-ec13-793f-9a38-160bba2b7342" xlink:to="loc_us-gaap_ScheduleOfLineOfCreditFacilitiesTextBlock_01a068fb-ec13-7a19-a23c-dd5d460ab49b" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/SelectedBalanceSheetDataAccountsReceivableNetDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#SelectedBalanceSheetDataAccountsReceivableNetDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/SelectedBalanceSheetDataAccountsReceivableNetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_01a068fb-ec13-7d01-99d4-9f2fd9a9372d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_01a068fb-ec13-773a-a396-8e21eab79003" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a068fb-ec13-7d01-99d4-9f2fd9a9372d" xlink:to="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_01a068fb-ec13-773a-a396-8e21eab79003" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ec13-72f9-bd4b-d415e2a916b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_01a068fb-ec13-773a-a396-8e21eab79003" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ec13-72f9-bd4b-d415e2a916b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-72f9-bd4b-d415e2a916b6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ec13-72f9-bd4b-d415e2a916b6" xlink:to="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-72f9-bd4b-d415e2a916b6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-7b73-9040-81e08468c9ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ec13-72f9-bd4b-d415e2a916b6" xlink:to="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-7b73-9040-81e08468c9ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_01a068fb-ec13-72a7-b831-d7eaed5b8e01" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-7b73-9040-81e08468c9ea" xlink:to="loc_us-gaap_NonrelatedPartyMember_01a068fb-ec13-72a7-b831-d7eaed5b8e01" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableGrossCurrent_01a068fb-ec13-7a4c-b7a0-2c641d7c39b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableGrossCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a068fb-ec13-7d01-99d4-9f2fd9a9372d" xlink:to="loc_us-gaap_AccountsReceivableGrossCurrent_01a068fb-ec13-7a4c-b7a0-2c641d7c39b0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_01a068fb-ec13-768b-9021-2d17bce50efc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a068fb-ec13-7d01-99d4-9f2fd9a9372d" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_01a068fb-ec13-768b-9021-2d17bce50efc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_01a068fb-ec13-7888-b4cb-2d77701d0138" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a068fb-ec13-7d01-99d4-9f2fd9a9372d" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_01a068fb-ec13-7888-b4cb-2d77701d0138" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/SelectedBalanceSheetDataSelectedBalanceSheetDataInventoriesDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#SelectedBalanceSheetDataSelectedBalanceSheetDataInventoriesDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/SelectedBalanceSheetDataSelectedBalanceSheetDataInventoriesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_01a068fb-ec13-737d-8bcf-047d0fcab8d9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_01a068fb-ec13-76e2-8cbd-2a9e1b0cf94d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_01a068fb-ec13-737d-8bcf-047d0fcab8d9" xlink:to="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_01a068fb-ec13-76e2-8cbd-2a9e1b0cf94d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesInventoryAxis_01a068fb-ec13-7b59-806d-93893d85eba3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesInventoryAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_01a068fb-ec13-76e2-8cbd-2a9e1b0cf94d" xlink:to="loc_us-gaap_PublicUtilitiesInventoryAxis_01a068fb-ec13-7b59-806d-93893d85eba3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_01a068fb-ec13-7b59-806d-93893d85eba3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesInventoryTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PublicUtilitiesInventoryAxis_01a068fb-ec13-7b59-806d-93893d85eba3" xlink:to="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_01a068fb-ec13-7b59-806d-93893d85eba3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_01a068fb-ec13-7d98-a746-e04cd0c75d8a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesInventoryTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PublicUtilitiesInventoryAxis_01a068fb-ec13-7b59-806d-93893d85eba3" xlink:to="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_01a068fb-ec13-7d98-a746-e04cd0c75d8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesInventorySuppliesMember_01a068fb-ec13-7191-935a-528941e5713f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesInventorySuppliesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_01a068fb-ec13-7d98-a746-e04cd0c75d8a" xlink:to="loc_us-gaap_PublicUtilitiesInventorySuppliesMember_01a068fb-ec13-7191-935a-528941e5713f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesInventoryFuelMember_01a068fb-ec13-700a-94f8-50c8f25fade4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesInventoryFuelMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesInventoryTypeDomain_01a068fb-ec13-7d98-a746-e04cd0c75d8a" xlink:to="loc_us-gaap_PublicUtilitiesInventoryFuelMember_01a068fb-ec13-700a-94f8-50c8f25fade4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_01a068fb-ec13-74a4-b18e-24bfa9dd4420" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_01a068fb-ec13-737d-8bcf-047d0fcab8d9" xlink:to="loc_us-gaap_InventoryNet_01a068fb-ec13-74a4-b18e-24bfa9dd4420" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesInventory_01a068fb-ec13-734f-a854-d07d195ac30f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesInventory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_01a068fb-ec13-737d-8bcf-047d0fcab8d9" xlink:to="loc_us-gaap_PublicUtilitiesInventory_01a068fb-ec13-734f-a854-d07d195ac30f" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/BorrowingsandOtherFinancingInstrumentsMoneyPoolDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#BorrowingsandOtherFinancingInstrumentsMoneyPoolDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/BorrowingsandOtherFinancingInstrumentsMoneyPoolDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7623-ab8f-15a3106e1eb0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShortTermDebtTable_01a068fb-ec13-7576-95d7-757dd9d78823" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShortTermDebtTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7623-ab8f-15a3106e1eb0" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTable_01a068fb-ec13-7576-95d7-757dd9d78823" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-76f7-887d-43660974a620" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_01a068fb-ec13-7576-95d7-757dd9d78823" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-76f7-887d-43660974a620" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-76f7-887d-43660974a620_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-76f7-887d-43660974a620" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-76f7-887d-43660974a620_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7ab9-80ef-46fcf53f52a4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-76f7-887d-43660974a620" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7ab9-80ef-46fcf53f52a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_MoneyPoolMember_01a068fb-ec13-74cd-a4b5-80683408ff6b" xlink:href="sps-20260930.xsd#sps_MoneyPoolMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7ab9-80ef-46fcf53f52a4" xlink:to="loc_sps_MoneyPoolMember_01a068fb-ec13-74cd-a4b5-80683408ff6b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_01a068fb-ec13-7992-b655-79690c602147" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7623-ab8f-15a3106e1eb0" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_01a068fb-ec13-7992-b655-79690c602147" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_01a068fb-ec13-76c5-975c-ed74fe4d43e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7623-ab8f-15a3106e1eb0" xlink:to="loc_us-gaap_ShortTermBorrowings_01a068fb-ec13-76c5-975c-ed74fe4d43e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShorttermDebtAverageOutstandingAmount_01a068fb-ec13-7554-b2ca-f5b1e9f5a353" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShorttermDebtAverageOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7623-ab8f-15a3106e1eb0" xlink:to="loc_us-gaap_ShorttermDebtAverageOutstandingAmount_01a068fb-ec13-7554-b2ca-f5b1e9f5a353" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShorttermDebtMaximumAmountOutstandingDuringPeriod_01a068fb-ec13-7c5f-85c6-ba1a12f2f56c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShorttermDebtMaximumAmountOutstandingDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7623-ab8f-15a3106e1eb0" xlink:to="loc_us-gaap_ShorttermDebtMaximumAmountOutstandingDuringPeriod_01a068fb-ec13-7c5f-85c6-ba1a12f2f56c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_01a068fb-ec13-783b-822f-53d7ec27a53d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityInterestRateDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7623-ab8f-15a3106e1eb0" xlink:to="loc_us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_01a068fb-ec13-783b-822f-53d7ec27a53d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_01a068fb-ec13-771b-9a9e-2d254d5f4ec6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7623-ab8f-15a3106e1eb0" xlink:to="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_01a068fb-ec13-771b-9a9e-2d254d5f4ec6" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/BorrowingsandOtherFinancingInstrumentsCommercialPaperDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#BorrowingsandOtherFinancingInstrumentsCommercialPaperDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/BorrowingsandOtherFinancingInstrumentsCommercialPaperDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7261-b0b5-c42d75abfb7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShortTermDebtTable_01a068fb-ec13-7e3e-bd7a-d9cd05344a09" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShortTermDebtTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7261-b0b5-c42d75abfb7d" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTable_01a068fb-ec13-7e3e-bd7a-d9cd05344a09" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-7710-a58d-465052144f71" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_01a068fb-ec13-7e3e-bd7a-d9cd05344a09" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-7710-a58d-465052144f71" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7710-a58d-465052144f71_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-7710-a58d-465052144f71" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7710-a58d-465052144f71_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-74be-bdec-a4827f496105" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-7710-a58d-465052144f71" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-74be-bdec-a4827f496105" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_01a068fb-ec13-7222-b275-17e29b1313a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-74be-bdec-a4827f496105" xlink:to="loc_us-gaap_CommercialPaperMember_01a068fb-ec13-7222-b275-17e29b1313a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a068fb-ec13-708d-b8de-e47626f9db4f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_01a068fb-ec13-7e3e-bd7a-d9cd05344a09" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a068fb-ec13-708d-b8de-e47626f9db4f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-708d-b8de-e47626f9db4f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a068fb-ec13-708d-b8de-e47626f9db4f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-708d-b8de-e47626f9db4f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-7725-b964-2d5e98af6ea4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a068fb-ec13-708d-b8de-e47626f9db4f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-7725-b964-2d5e98af6ea4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_SeriesDueAugust152036Member_01a068fb-ec13-707a-be8a-c656aa30afb0" xlink:href="sps-20260930.xsd#sps_SeriesDueAugust152036Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-7725-b964-2d5e98af6ea4" xlink:to="loc_sps_SeriesDueAugust152036Member_01a068fb-ec13-707a-be8a-c656aa30afb0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_01a068fb-ec13-75ec-bc04-2d2f842d479e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_01a068fb-ec13-7e3e-bd7a-d9cd05344a09" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_01a068fb-ec13-75ec-bc04-2d2f842d479e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a068fb-ec13-75ec-bc04-2d2f842d479e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a068fb-ec13-75ec-bc04-2d2f842d479e" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a068fb-ec13-75ec-bc04-2d2f842d479e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a068fb-ec13-7fd5-96f7-990ca9b23f13" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a068fb-ec13-75ec-bc04-2d2f842d479e" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a068fb-ec13-7fd5-96f7-990ca9b23f13" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BondsMember_01a068fb-ec13-7d1f-bdcc-9e4425d78391" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BondsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a068fb-ec13-7fd5-96f7-990ca9b23f13" xlink:to="loc_us-gaap_BondsMember_01a068fb-ec13-7d1f-bdcc-9e4425d78391" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_01a068fb-ec13-7be1-8ead-450cb1304293" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_01a068fb-ec13-7e3e-bd7a-d9cd05344a09" xlink:to="loc_dei_LegalEntityAxis_01a068fb-ec13-7be1-8ead-450cb1304293" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_01a068fb-ec13-7be1-8ead-450cb1304293_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_01a068fb-ec13-7be1-8ead-450cb1304293" xlink:to="loc_dei_EntityDomain_01a068fb-ec13-7be1-8ead-450cb1304293_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_01a068fb-ec13-7acf-ac98-9fbb0ba987f4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_01a068fb-ec13-7be1-8ead-450cb1304293" xlink:to="loc_dei_EntityDomain_01a068fb-ec13-7acf-ac98-9fbb0ba987f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_SpsMember_01a068fb-ec13-75b8-b497-ebda2e397e61" xlink:href="sps-20260930.xsd#sps_SpsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_01a068fb-ec13-7acf-ac98-9fbb0ba987f4" xlink:to="loc_sps_SpsMember_01a068fb-ec13-75b8-b497-ebda2e397e61" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_01a068fb-ec13-746d-bd6b-1469d928f171" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7261-b0b5-c42d75abfb7d" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_01a068fb-ec13-746d-bd6b-1469d928f171" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_01a068fb-ec13-7257-986c-5296814b5ce9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7261-b0b5-c42d75abfb7d" xlink:to="loc_us-gaap_ShortTermBorrowings_01a068fb-ec13-7257-986c-5296814b5ce9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShorttermDebtAverageOutstandingAmount_01a068fb-ec13-7555-ae39-f92c42408621" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShorttermDebtAverageOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7261-b0b5-c42d75abfb7d" xlink:to="loc_us-gaap_ShorttermDebtAverageOutstandingAmount_01a068fb-ec13-7555-ae39-f92c42408621" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShorttermDebtMaximumAmountOutstandingDuringPeriod_01a068fb-ec13-7ea5-9713-489f907ede75" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShorttermDebtMaximumAmountOutstandingDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7261-b0b5-c42d75abfb7d" xlink:to="loc_us-gaap_ShorttermDebtMaximumAmountOutstandingDuringPeriod_01a068fb-ec13-7ea5-9713-489f907ede75" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_01a068fb-ec13-7613-ba14-a585c0dc376e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityInterestRateDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7261-b0b5-c42d75abfb7d" xlink:to="loc_us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_01a068fb-ec13-7613-ba14-a585c0dc376e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_01a068fb-ec13-77cb-90a3-b1c23ef1d697" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_01a068fb-ec13-7261-b0b5-c42d75abfb7d" xlink:to="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_01a068fb-ec13-77cb-90a3-b1c23ef1d697" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/BorrowingsandOtherFinancingInstrumentsLettersofCreditDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#BorrowingsandOtherFinancingInstrumentsLettersofCreditDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/BorrowingsandOtherFinancingInstrumentsLettersofCreditDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_01a068fb-ec13-78c5-8e57-5ceee2e7b956" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_01a068fb-ec13-711f-a44b-e8d99af56ed0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_01a068fb-ec13-78c5-8e57-5ceee2e7b956" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_01a068fb-ec13-711f-a44b-e8d99af56ed0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_01a068fb-ec13-701c-94f5-843b40c90e2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_01a068fb-ec13-711f-a44b-e8d99af56ed0" xlink:to="loc_us-gaap_CreditFacilityAxis_01a068fb-ec13-701c-94f5-843b40c90e2d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_01a068fb-ec13-701c-94f5-843b40c90e2d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_01a068fb-ec13-701c-94f5-843b40c90e2d" xlink:to="loc_us-gaap_CreditFacilityDomain_01a068fb-ec13-701c-94f5-843b40c90e2d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_01a068fb-ec13-76ea-8f58-262ed86745db" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_01a068fb-ec13-701c-94f5-843b40c90e2d" xlink:to="loc_us-gaap_CreditFacilityDomain_01a068fb-ec13-76ea-8f58-262ed86745db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_01a068fb-ec13-7010-8dcf-5f1cc8342373" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_01a068fb-ec13-76ea-8f58-262ed86745db" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_01a068fb-ec13-7010-8dcf-5f1cc8342373" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_01a068fb-ec13-734f-85df-cc926a8087dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_01a068fb-ec13-76ea-8f58-262ed86745db" xlink:to="loc_us-gaap_LetterOfCreditMember_01a068fb-ec13-734f-85df-cc926a8087dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-7032-99f1-52315f116fd6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_01a068fb-ec13-711f-a44b-e8d99af56ed0" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-7032-99f1-52315f116fd6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7032-99f1-52315f116fd6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-7032-99f1-52315f116fd6" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7032-99f1-52315f116fd6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7674-90d3-ad537c448155" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_01a068fb-ec13-7032-99f1-52315f116fd6" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7674-90d3-ad537c448155" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_01a068fb-ec13-7579-ac5b-53b1e9eab839" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_01a068fb-ec13-7674-90d3-ad537c448155" xlink:to="loc_us-gaap_LetterOfCreditMember_01a068fb-ec13-7579-ac5b-53b1e9eab839" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a068fb-ec13-7487-b27f-3d83f5b5c8b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_01a068fb-ec13-711f-a44b-e8d99af56ed0" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a068fb-ec13-7487-b27f-3d83f5b5c8b4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-7487-b27f-3d83f5b5c8b4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a068fb-ec13-7487-b27f-3d83f5b5c8b4" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-7487-b27f-3d83f5b5c8b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-7cd9-8d2c-9e7b9798c7ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a068fb-ec13-7487-b27f-3d83f5b5c8b4" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-7cd9-8d2c-9e7b9798c7ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_ContinuingLetterOfCreditAgreementMember_01a068fb-ec13-78c2-b383-aca6a723c2dd" xlink:href="sps-20260930.xsd#sps_ContinuingLetterOfCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-7cd9-8d2c-9e7b9798c7ed" xlink:to="loc_sps_ContinuingLetterOfCreditAgreementMember_01a068fb-ec13-78c2-b383-aca6a723c2dd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_01a068fb-ec13-76bd-b3db-eda2d88ac47e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_01a068fb-ec13-78c5-8e57-5ceee2e7b956" xlink:to="loc_us-gaap_ShortTermBorrowings_01a068fb-ec13-76bd-b3db-eda2d88ac47e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_01a068fb-ec13-7398-9e05-0b3415c9d7c8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_01a068fb-ec13-78c5-8e57-5ceee2e7b956" xlink:to="loc_us-gaap_LineOfCredit_01a068fb-ec13-7398-9e05-0b3415c9d7c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_01a068fb-ec13-7dd6-b4c1-e681615ed788" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_01a068fb-ec13-78c5-8e57-5ceee2e7b956" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_01a068fb-ec13-7dd6-b4c1-e681615ed788" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/BorrowingsandOtherFinancingInstrumentsCreditFacilityDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#BorrowingsandOtherFinancingInstrumentsCreditFacilityDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/BorrowingsandOtherFinancingInstrumentsCreditFacilityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_01a068fb-ec13-740c-9676-9eed0f3ff5a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_01a068fb-ec13-7154-9cfb-a0406b106c74" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_01a068fb-ec13-740c-9676-9eed0f3ff5a5" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_01a068fb-ec13-7154-9cfb-a0406b106c74" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_01a068fb-ec13-73d8-95c9-239f3092772a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_01a068fb-ec13-7154-9cfb-a0406b106c74" xlink:to="loc_us-gaap_CreditFacilityAxis_01a068fb-ec13-73d8-95c9-239f3092772a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_01a068fb-ec13-73d8-95c9-239f3092772a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_01a068fb-ec13-73d8-95c9-239f3092772a" xlink:to="loc_us-gaap_CreditFacilityDomain_01a068fb-ec13-73d8-95c9-239f3092772a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_01a068fb-ec13-7359-87c3-c7fac7227778" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_01a068fb-ec13-73d8-95c9-239f3092772a" xlink:to="loc_us-gaap_CreditFacilityDomain_01a068fb-ec13-7359-87c3-c7fac7227778" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_01a068fb-ec13-7430-a5f6-0adad0587730" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_01a068fb-ec13-7359-87c3-c7fac7227778" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_01a068fb-ec13-7430-a5f6-0adad0587730" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_01a068fb-ec13-7f67-954e-9ff6361a9a82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_01a068fb-ec13-740c-9676-9eed0f3ff5a5" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_01a068fb-ec13-7f67-954e-9ff6361a9a82" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityFairValueOfAmountOutstanding_01a068fb-ec13-77de-8e92-352790e92394" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityFairValueOfAmountOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_01a068fb-ec13-740c-9676-9eed0f3ff5a5" xlink:to="loc_us-gaap_LineOfCreditFacilityFairValueOfAmountOutstanding_01a068fb-ec13-77de-8e92-352790e92394" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_01a068fb-ec13-7f92-b0f6-c5bfe986d7cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_01a068fb-ec13-740c-9676-9eed0f3ff5a5" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_01a068fb-ec13-7f92-b0f6-c5bfe986d7cf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_01a068fb-ec13-7331-bebb-6e8b52a01f8a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_01a068fb-ec13-740c-9676-9eed0f3ff5a5" xlink:to="loc_us-gaap_LineOfCredit_01a068fb-ec13-7331-bebb-6e8b52a01f8a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_NumberOfExtensionYouCanRequest_01a068fb-ec13-73ad-81d9-500865c1e35a" xlink:href="sps-20260930.xsd#sps_NumberOfExtensionYouCanRequest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_01a068fb-ec13-740c-9676-9eed0f3ff5a5" xlink:to="loc_sps_NumberOfExtensionYouCanRequest_01a068fb-ec13-73ad-81d9-500865c1e35a" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/BorrowingsandOtherFinancingInstrumentsLongTermBorrowingsDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#BorrowingsandOtherFinancingInstrumentsLongTermBorrowingsDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/BorrowingsandOtherFinancingInstrumentsLongTermBorrowingsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_01a068fb-ec13-7e91-90a2-b0392c319c67" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_01a068fb-ec13-770d-8e47-86438745e3ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a068fb-ec13-7e91-90a2-b0392c319c67" xlink:to="loc_us-gaap_DebtInstrumentTable_01a068fb-ec13-770d-8e47-86438745e3ac" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a068fb-ec13-78fe-bd7a-39f721774b20" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a068fb-ec13-770d-8e47-86438745e3ac" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a068fb-ec13-78fe-bd7a-39f721774b20" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-78fe-bd7a-39f721774b20_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a068fb-ec13-78fe-bd7a-39f721774b20" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-78fe-bd7a-39f721774b20_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-7fa4-a8f4-41a8077ce9e7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a068fb-ec13-78fe-bd7a-39f721774b20" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-7fa4-a8f4-41a8077ce9e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_SeriesDueAugust152036Member_01a068fb-ec13-7bfb-9568-cc990cc96a72" xlink:href="sps-20260930.xsd#sps_SeriesDueAugust152036Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-7fa4-a8f4-41a8077ce9e7" xlink:to="loc_sps_SeriesDueAugust152036Member_01a068fb-ec13-7bfb-9568-cc990cc96a72" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_SeriesDueAugust152056Member_01a068fb-ec13-7537-94de-64553ae5e4ed" xlink:href="sps-20260930.xsd#sps_SeriesDueAugust152056Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a068fb-ec13-7fa4-a8f4-41a8077ce9e7" xlink:to="loc_sps_SeriesDueAugust152056Member_01a068fb-ec13-7537-94de-64553ae5e4ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_01a068fb-ec13-7b27-8dc3-a3af38e3f248" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a068fb-ec13-770d-8e47-86438745e3ac" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_01a068fb-ec13-7b27-8dc3-a3af38e3f248" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a068fb-ec13-7b27-8dc3-a3af38e3f248_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a068fb-ec13-7b27-8dc3-a3af38e3f248" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a068fb-ec13-7b27-8dc3-a3af38e3f248_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a068fb-ec13-7edd-83f8-b4f7a4dbffd7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a068fb-ec13-7b27-8dc3-a3af38e3f248" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a068fb-ec13-7edd-83f8-b4f7a4dbffd7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BondsMember_01a068fb-ec13-71b0-b56e-fbbecc82b7e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BondsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a068fb-ec13-7edd-83f8-b4f7a4dbffd7" xlink:to="loc_us-gaap_BondsMember_01a068fb-ec13-71b0-b56e-fbbecc82b7e1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_01a068fb-ec13-77b2-ab22-287911c9b960" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a068fb-ec13-770d-8e47-86438745e3ac" xlink:to="loc_dei_LegalEntityAxis_01a068fb-ec13-77b2-ab22-287911c9b960" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_01a068fb-ec13-77b2-ab22-287911c9b960_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_01a068fb-ec13-77b2-ab22-287911c9b960" xlink:to="loc_dei_EntityDomain_01a068fb-ec13-77b2-ab22-287911c9b960_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_01a068fb-ec13-7caa-8f8a-5d5ff6ea9521" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_01a068fb-ec13-77b2-ab22-287911c9b960" xlink:to="loc_dei_EntityDomain_01a068fb-ec13-7caa-8f8a-5d5ff6ea9521" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_SpsMember_01a068fb-ec13-79e8-9625-7d929d186654" xlink:href="sps-20260930.xsd#sps_SpsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_01a068fb-ec13-7caa-8f8a-5d5ff6ea9521" xlink:to="loc_sps_SpsMember_01a068fb-ec13-79e8-9625-7d929d186654" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ec13-71a1-8047-1023a8626b37" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a068fb-ec13-770d-8e47-86438745e3ac" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ec13-71a1-8047-1023a8626b37" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-71a1-8047-1023a8626b37_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ec13-71a1-8047-1023a8626b37" xlink:to="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-71a1-8047-1023a8626b37_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-7786-a405-b3d4d0c42212" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ec13-71a1-8047-1023a8626b37" xlink:to="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-7786-a405-b3d4d0c42212" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_SpsMember_01a068fb-ec13-79b6-901d-651c09c8b6c9" xlink:href="sps-20260930.xsd#sps_SpsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a068fb-ec13-7786-a405-b3d4d0c42212" xlink:to="loc_sps_SpsMember_01a068fb-ec13-79b6-901d-651c09c8b6c9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_01a068fb-ec13-7ae0-b0ea-eaaf28ca1e31" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a068fb-ec13-7e91-90a2-b0392c319c67" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_01a068fb-ec13-7ae0-b0ea-eaaf28ca1e31" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_01a068fb-ec13-7bc2-94ec-e795ab8560f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a068fb-ec13-7e91-90a2-b0392c319c67" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_01a068fb-ec13-7bc2-94ec-e795ab8560f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_01a068fb-ec13-7e70-8386-0dee9662fb6a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRepurchasedFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a068fb-ec13-7e91-90a2-b0392c319c67" xlink:to="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_01a068fb-ec13-7e70-8386-0dee9662fb6a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRepurchaseAmount_01a068fb-ecbd-7a1b-9dfc-d8af5efd2171" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRepurchaseAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a068fb-ec13-7e91-90a2-b0392c319c67" xlink:to="loc_us-gaap_DebtInstrumentRepurchaseAmount_01a068fb-ecbd-7a1b-9dfc-d8af5efd2171" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/RevenuesDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#RevenuesDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/RevenuesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_01a068fb-ecbd-7efc-b1f5-1808caf1832d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_01a068fb-ecbd-796c-a9d7-e68125936dc9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_01a068fb-ecbd-7efc-b1f5-1808caf1832d" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_01a068fb-ecbd-796c-a9d7-e68125936dc9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_01a068fb-ecbd-705e-acc1-77737721a81c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_01a068fb-ecbd-796c-a9d7-e68125936dc9" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_01a068fb-ecbd-705e-acc1-77737721a81c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_01a068fb-ecbd-705e-acc1-77737721a81c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01a068fb-ecbd-705e-acc1-77737721a81c" xlink:to="loc_us-gaap_SegmentDomain_01a068fb-ecbd-705e-acc1-77737721a81c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_01a068fb-ecbd-74c0-9a97-b7fc9e4006dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01a068fb-ecbd-705e-acc1-77737721a81c" xlink:to="loc_us-gaap_SegmentDomain_01a068fb-ecbd-74c0-9a97-b7fc9e4006dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_RegulatedElectricMember_01a068fb-ecbd-7b87-b8f1-24a65e892662" xlink:href="sps-20260930.xsd#sps_RegulatedElectricMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_01a068fb-ecbd-74c0-9a97-b7fc9e4006dc" xlink:to="loc_sps_RegulatedElectricMember_01a068fb-ecbd-7b87-b8f1-24a65e892662" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_01a068fb-ecbd-7a0d-82e9-b27c5f403fcc" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_01a068fb-ecbd-796c-a9d7-e68125936dc9" xlink:to="loc_srt_ProductOrServiceAxis_01a068fb-ecbd-7a0d-82e9-b27c5f403fcc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_01a068fb-ecbd-7a0d-82e9-b27c5f403fcc_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_01a068fb-ecbd-7a0d-82e9-b27c5f403fcc" xlink:to="loc_srt_ProductsAndServicesDomain_01a068fb-ecbd-7a0d-82e9-b27c5f403fcc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_01a068fb-ecbd-71af-b1ba-1b448fd6881c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_01a068fb-ecbd-7a0d-82e9-b27c5f403fcc" xlink:to="loc_srt_ProductsAndServicesDomain_01a068fb-ecbd-71af-b1ba-1b448fd6881c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_RetailDistributionMember_01a068fb-ecbd-7584-854d-00e13d4ff116" xlink:href="sps-20260930.xsd#sps_RetailDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_01a068fb-ecbd-71af-b1ba-1b448fd6881c" xlink:to="loc_sps_RetailDistributionMember_01a068fb-ecbd-7584-854d-00e13d4ff116" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_WholesaleDistributionMember_01a068fb-ecbd-7682-9714-bb76844ee1b7" xlink:href="sps-20260930.xsd#sps_WholesaleDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_01a068fb-ecbd-71af-b1ba-1b448fd6881c" xlink:to="loc_sps_WholesaleDistributionMember_01a068fb-ecbd-7682-9714-bb76844ee1b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_TransmissionServicesMember_01a068fb-ecbd-7a72-8a22-a56bb17f9ce6" xlink:href="sps-20260930.xsd#sps_TransmissionServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_01a068fb-ecbd-71af-b1ba-1b448fd6881c" xlink:to="loc_sps_TransmissionServicesMember_01a068fb-ecbd-7a72-8a22-a56bb17f9ce6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_AlternativeandOtherMember_01a068fb-ecbd-733c-9425-f46d65f25550" xlink:href="sps-20260930.xsd#sps_AlternativeandOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_01a068fb-ecbd-71af-b1ba-1b448fd6881c" xlink:to="loc_sps_AlternativeandOtherMember_01a068fb-ecbd-733c-9425-f46d65f25550" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_OtherServicesMember_01a068fb-ecbd-7010-b695-00628b34550b" xlink:href="sps-20260930.xsd#sps_OtherServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_01a068fb-ecbd-71af-b1ba-1b448fd6881c" xlink:to="loc_sps_OtherServicesMember_01a068fb-ecbd-7010-b695-00628b34550b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_01a068fb-ecbd-7d5f-9b63-a637ca5cd923" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_01a068fb-ecbd-796c-a9d7-e68125936dc9" xlink:to="loc_srt_MajorCustomersAxis_01a068fb-ecbd-7d5f-9b63-a637ca5cd923" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_01a068fb-ecbd-7d5f-9b63-a637ca5cd923_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_01a068fb-ecbd-7d5f-9b63-a637ca5cd923" xlink:to="loc_srt_NameOfMajorCustomerDomain_01a068fb-ecbd-7d5f-9b63-a637ca5cd923_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_01a068fb-ecbd-7a10-b811-5a79e962c39b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_01a068fb-ecbd-7d5f-9b63-a637ca5cd923" xlink:to="loc_srt_NameOfMajorCustomerDomain_01a068fb-ecbd-7a10-b811-5a79e962c39b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_ResidentialCustomersMember_01a068fb-ecbd-7ebd-82f6-96c70e5c7539" xlink:href="sps-20260930.xsd#sps_ResidentialCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_01a068fb-ecbd-7a10-b811-5a79e962c39b" xlink:to="loc_sps_ResidentialCustomersMember_01a068fb-ecbd-7ebd-82f6-96c70e5c7539" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_CommercialandIndustrialCustomersMember_01a068fb-ecbd-7823-beb7-8304f8773138" xlink:href="sps-20260930.xsd#sps_CommercialandIndustrialCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_01a068fb-ecbd-7a10-b811-5a79e962c39b" xlink:to="loc_sps_CommercialandIndustrialCustomersMember_01a068fb-ecbd-7823-beb7-8304f8773138" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_OtherCustomersMember_01a068fb-ecbd-757a-92b5-233f584be919" xlink:href="sps-20260930.xsd#sps_OtherCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_01a068fb-ecbd-7a10-b811-5a79e962c39b" xlink:to="loc_sps_OtherCustomersMember_01a068fb-ecbd-757a-92b5-233f584be919" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_01a068fb-ecbd-7639-ad02-339e63db3d9c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_01a068fb-ecbd-796c-a9d7-e68125936dc9" xlink:to="loc_srt_ConsolidationItemsAxis_01a068fb-ecbd-7639-ad02-339e63db3d9c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_01a068fb-ecbd-7639-ad02-339e63db3d9c_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_01a068fb-ecbd-7639-ad02-339e63db3d9c" xlink:to="loc_srt_ConsolidationItemsDomain_01a068fb-ecbd-7639-ad02-339e63db3d9c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_01a068fb-ecbd-70ee-8218-4c3ce2ffb867" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_01a068fb-ecbd-7639-ad02-339e63db3d9c" xlink:to="loc_srt_ConsolidationItemsDomain_01a068fb-ecbd-70ee-8218-4c3ce2ffb867" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_01a068fb-ecbd-76f5-a9d9-ba6b5047152e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_01a068fb-ecbd-70ee-8218-4c3ce2ffb867" xlink:to="loc_us-gaap_OperatingSegmentsMember_01a068fb-ecbd-76f5-a9d9-ba6b5047152e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a068fb-ecbd-74f6-bbdf-acfa2abba1a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_01a068fb-ecbd-7efc-b1f5-1808caf1832d" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a068fb-ecbd-74f6-bbdf-acfa2abba1a8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueNotFromContractWithCustomer_01a068fb-ecbd-783a-b07f-33b7f8843d4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueNotFromContractWithCustomer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_01a068fb-ecbd-7efc-b1f5-1808caf1832d" xlink:to="loc_us-gaap_RevenueNotFromContractWithCustomer_01a068fb-ecbd-783a-b07f-33b7f8843d4c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_01a068fb-ecbd-7735-9f4c-5520354fc3e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_01a068fb-ecbd-7efc-b1f5-1808caf1832d" xlink:to="loc_us-gaap_Revenues_01a068fb-ecbd-7735-9f4c-5520354fc3e1" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/FairValueofFinancialAssetsandLiabilitiesCommodityDerivativesDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#FairValueofFinancialAssetsandLiabilitiesCommodityDerivativesDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/FairValueofFinancialAssetsandLiabilitiesCommodityDerivativesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-7d55-b6d2-f73b68b6b967" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_01a068fb-ecbd-7229-9354-291f719e1f7e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-7d55-b6d2-f73b68b6b967" xlink:to="loc_us-gaap_DerivativeTable_01a068fb-ecbd-7229-9354-291f719e1f7e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7226-b711-7e84ee2cfd77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_01a068fb-ecbd-7229-9354-291f719e1f7e" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7226-b711-7e84ee2cfd77" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7226-b711-7e84ee2cfd77_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7226-b711-7e84ee2cfd77" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7226-b711-7e84ee2cfd77_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7206-a095-953c686e6357" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7226-b711-7e84ee2cfd77" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7206-a095-953c686e6357" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_ElectricCommodityMember_01a068fb-ecbd-77db-b3b0-61862e68104a" xlink:href="sps-20260930.xsd#sps_ElectricCommodityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7206-a095-953c686e6357" xlink:to="loc_sps_ElectricCommodityMember_01a068fb-ecbd-77db-b3b0-61862e68104a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_CashflowhedgecommodityMember_01a068fb-ecbd-7965-9a43-9a2d13610182" xlink:href="sps-20260930.xsd#sps_CashflowhedgecommodityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7206-a095-953c686e6357" xlink:to="loc_sps_CashflowhedgecommodityMember_01a068fb-ecbd-7965-9a43-9a2d13610182" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_ElectricCommodityContractMember_01a068fb-ecbd-7264-a780-3acc45781c4f" xlink:href="sps-20260930.xsd#sps_ElectricCommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7206-a095-953c686e6357" xlink:to="loc_sps_ElectricCommodityContractMember_01a068fb-ecbd-7264-a780-3acc45781c4f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_01a068fb-ecbd-7771-b6bf-b8f601ab5668" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_01a068fb-ecbd-7229-9354-291f719e1f7e" xlink:to="loc_us-gaap_HedgingDesignationAxis_01a068fb-ecbd-7771-b6bf-b8f601ab5668" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-7771-b6bf-b8f601ab5668_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_01a068fb-ecbd-7771-b6bf-b8f601ab5668" xlink:to="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-7771-b6bf-b8f601ab5668_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-7b35-aa25-85d467f6369d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_01a068fb-ecbd-7771-b6bf-b8f601ab5668" xlink:to="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-7b35-aa25-85d467f6369d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_01a068fb-ecbd-745d-a856-f5ef88a1977e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-7b35-aa25-85d467f6369d" xlink:to="loc_us-gaap_NondesignatedMember_01a068fb-ecbd-745d-a856-f5ef88a1977e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNonmonetaryNotionalAmount_01a068fb-ecbd-72c0-b828-549ac5e52331" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeNonmonetaryNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-7d55-b6d2-f73b68b6b967" xlink:to="loc_us-gaap_DerivativeNonmonetaryNotionalAmount_01a068fb-ecbd-72c0-b828-549ac5e52331" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_Commoditycontractsdesignatedascashflowhedges_01a068fb-ecbd-726e-8a6e-c36fa9f05011" xlink:href="sps-20260930.xsd#sps_Commoditycontractsdesignatedascashflowhedges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-7d55-b6d2-f73b68b6b967" xlink:to="loc_sps_Commoditycontractsdesignatedascashflowhedges_01a068fb-ecbd-726e-8a6e-c36fa9f05011" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_Pretaxgainslossesreclassifiedintoincomeduringtheperiodfromregulatoryassetsandliabilities_01a068fb-ecbd-7dce-8c85-b2411355b80f" xlink:href="sps-20260930.xsd#sps_Pretaxgainslossesreclassifiedintoincomeduringtheperiodfromregulatoryassetsandliabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-7d55-b6d2-f73b68b6b967" xlink:to="loc_sps_Pretaxgainslossesreclassifiedintoincomeduringtheperiodfromregulatoryassetsandliabilities_01a068fb-ecbd-7dce-8c85-b2411355b80f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/FairValueofFinancialAssetsandLiabilitiesConsiderationofCreditRiskConcentrationsDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#FairValueofFinancialAssetsandLiabilitiesConsiderationofCreditRiskConcentrationsDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/FairValueofFinancialAssetsandLiabilitiesConsiderationofCreditRiskConcentrationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-7d92-a94f-ccdc815a8334" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_01a068fb-ecbd-72e1-8815-304d66724278" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-7d92-a94f-ccdc815a8334" xlink:to="loc_us-gaap_DerivativeTable_01a068fb-ecbd-72e1-8815-304d66724278" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_01a068fb-ecbd-70cf-a838-079e8fea112c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_01a068fb-ecbd-72e1-8815-304d66724278" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_01a068fb-ecbd-70cf-a838-079e8fea112c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_01a068fb-ecbd-70cf-a838-079e8fea112c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_01a068fb-ecbd-70cf-a838-079e8fea112c" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_01a068fb-ecbd-70cf-a838-079e8fea112c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_01a068fb-ecbd-742a-80a0-96e4fb960b65" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_01a068fb-ecbd-70cf-a838-079e8fea112c" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_01a068fb-ecbd-742a-80a0-96e4fb960b65" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditConcentrationRiskMember_01a068fb-ecbd-73ee-97e7-de075c374bb8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_01a068fb-ecbd-742a-80a0-96e4fb960b65" xlink:to="loc_us-gaap_CreditConcentrationRiskMember_01a068fb-ecbd-73ee-97e7-de075c374bb8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_CreditQualityIndicatorAxis_01a068fb-ecbd-7e22-a650-a3034a5b964f" xlink:href="sps-20260930.xsd#sps_CreditQualityIndicatorAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_01a068fb-ecbd-72e1-8815-304d66724278" xlink:to="loc_sps_CreditQualityIndicatorAxis_01a068fb-ecbd-7e22-a650-a3034a5b964f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_CreditQualityIndicatorDomain_01a068fb-ecbd-7e22-a650-a3034a5b964f_default" xlink:href="sps-20260930.xsd#sps_CreditQualityIndicatorDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_sps_CreditQualityIndicatorAxis_01a068fb-ecbd-7e22-a650-a3034a5b964f" xlink:to="loc_sps_CreditQualityIndicatorDomain_01a068fb-ecbd-7e22-a650-a3034a5b964f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_CreditQualityIndicatorDomain_01a068fb-ecbd-77b1-9203-5cd36665c5b4" xlink:href="sps-20260930.xsd#sps_CreditQualityIndicatorDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_sps_CreditQualityIndicatorAxis_01a068fb-ecbd-7e22-a650-a3034a5b964f" xlink:to="loc_sps_CreditQualityIndicatorDomain_01a068fb-ecbd-77b1-9203-5cd36665c5b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExternalCreditRatingInvestmentGradeMember_01a068fb-ecbd-772c-993d-3cfcfe43decb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ExternalCreditRatingInvestmentGradeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sps_CreditQualityIndicatorDomain_01a068fb-ecbd-77b1-9203-5cd36665c5b4" xlink:to="loc_us-gaap_ExternalCreditRatingInvestmentGradeMember_01a068fb-ecbd-772c-993d-3cfcfe43decb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalInvestmentGradeMember_01a068fb-ecbd-78a3-a1c4-7c981cb67e2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InternalInvestmentGradeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sps_CreditQualityIndicatorDomain_01a068fb-ecbd-77b1-9203-5cd36665c5b4" xlink:to="loc_us-gaap_InternalInvestmentGradeMember_01a068fb-ecbd-78a3-a1c4-7c981cb67e2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_Numberofmostsignificantcounterpartiesforwholesaletradingandnontradingcommodityactivitieswithcreditexposure_01a068fb-ecbd-78c1-b472-5b064db1d534" xlink:href="sps-20260930.xsd#sps_Numberofmostsignificantcounterpartiesforwholesaletradingandnontradingcommodityactivitieswithcreditexposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-7d92-a94f-ccdc815a8334" xlink:to="loc_sps_Numberofmostsignificantcounterpartiesforwholesaletradingandnontradingcommodityactivitieswithcreditexposure_01a068fb-ecbd-78c1-b472-5b064db1d534" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_WholesaleTradingAndNonTradingCommodityCreditExposureForMostSignificantCounterparties_01a068fb-ecbd-7c9d-993e-7a3d35ea4a49" xlink:href="sps-20260930.xsd#sps_WholesaleTradingAndNonTradingCommodityCreditExposureForMostSignificantCounterparties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-7d92-a94f-ccdc815a8334" xlink:to="loc_sps_WholesaleTradingAndNonTradingCommodityCreditExposureForMostSignificantCounterparties_01a068fb-ecbd-7c9d-993e-7a3d35ea4a49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_PercentageOfWholesaleTradingAndNonTradingCommodityCreditExposureForMostSignificantCounterparties_01a068fb-ecbd-7991-b120-80980b5e66f8" xlink:href="sps-20260930.xsd#sps_PercentageOfWholesaleTradingAndNonTradingCommodityCreditExposureForMostSignificantCounterparties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-7d92-a94f-ccdc815a8334" xlink:to="loc_sps_PercentageOfWholesaleTradingAndNonTradingCommodityCreditExposureForMostSignificantCounterparties_01a068fb-ecbd-7991-b120-80980b5e66f8" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/FairValueofFinancialAssetsandLiabilitiesImpactofDerivativeActivitiesonIncomeandAccumulatedOtherComprehensiveLossDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#FairValueofFinancialAssetsandLiabilitiesImpactofDerivativeActivitiesonIncomeandAccumulatedOtherComprehensiveLossDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/FairValueofFinancialAssetsandLiabilitiesImpactofDerivativeActivitiesonIncomeandAccumulatedOtherComprehensiveLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_01a068fb-ecbd-7c45-9a01-40b9cdc5c80b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_01a068fb-ecbd-70dd-a2b4-adff50082776" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_01a068fb-ecbd-7c45-9a01-40b9cdc5c80b" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_01a068fb-ecbd-70dd-a2b4-adff50082776" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_01a068fb-ecbd-71e4-a1c4-8956ea721f2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_01a068fb-ecbd-70dd-a2b4-adff50082776" xlink:to="loc_us-gaap_HedgingDesignationAxis_01a068fb-ecbd-71e4-a1c4-8956ea721f2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-71e4-a1c4-8956ea721f2a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_01a068fb-ecbd-71e4-a1c4-8956ea721f2a" xlink:to="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-71e4-a1c4-8956ea721f2a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-7cf2-87f1-ad1ea6482265" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_01a068fb-ecbd-71e4-a1c4-8956ea721f2a" xlink:to="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-7cf2-87f1-ad1ea6482265" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_01a068fb-ecbd-7f76-a9ca-15dcd29c4b9e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-7cf2-87f1-ad1ea6482265" xlink:to="loc_us-gaap_NondesignatedMember_01a068fb-ecbd-7f76-a9ca-15dcd29c4b9e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7868-86cf-aa1ed1206909" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_01a068fb-ecbd-70dd-a2b4-adff50082776" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7868-86cf-aa1ed1206909" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7868-86cf-aa1ed1206909_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7868-86cf-aa1ed1206909" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7868-86cf-aa1ed1206909_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-76c1-9cea-4278a081c7fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7868-86cf-aa1ed1206909" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-76c1-9cea-4278a081c7fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_ElectricCommodityContractMember_01a068fb-ecbd-7d1e-9c91-1f8c78ec03c7" xlink:href="sps-20260930.xsd#sps_ElectricCommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-76c1-9cea-4278a081c7fd" xlink:to="loc_sps_ElectricCommodityContractMember_01a068fb-ecbd-7d1e-9c91-1f8c78ec03c7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_01a068fb-ecbd-765c-9959-4744e7e2f6ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-76c1-9cea-4278a081c7fd" xlink:to="loc_us-gaap_InterestRateSwapMember_01a068fb-ecbd-765c-9959-4744e7e2f6ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_01a068fb-ecbd-7d3f-a799-da1df2467da4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-76c1-9cea-4278a081c7fd" xlink:to="loc_us-gaap_CommodityContractMember_01a068fb-ecbd-7d3f-a799-da1df2467da4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_ImpactOfDerivativeActivityOnAccumulatedOtherComprehensiveLossRegulatoryAssetsAndLiabilitiesAndIncomeAbstract_01a068fb-ecbd-73bd-a294-65c4295b8781" xlink:href="sps-20260930.xsd#sps_ImpactOfDerivativeActivityOnAccumulatedOtherComprehensiveLossRegulatoryAssetsAndLiabilitiesAndIncomeAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_01a068fb-ecbd-7c45-9a01-40b9cdc5c80b" xlink:to="loc_sps_ImpactOfDerivativeActivityOnAccumulatedOtherComprehensiveLossRegulatoryAssetsAndLiabilitiesAndIncomeAbstract_01a068fb-ecbd-73bd-a294-65c4295b8781" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgesAtFairValueNet_01a068fb-ecbd-77a6-96ad-4f72d699ba3c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueHedgesAtFairValueNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sps_ImpactOfDerivativeActivityOnAccumulatedOtherComprehensiveLossRegulatoryAssetsAndLiabilitiesAndIncomeAbstract_01a068fb-ecbd-73bd-a294-65c4295b8781" xlink:to="loc_us-gaap_FairValueHedgesAtFairValueNet_01a068fb-ecbd-77a6-96ad-4f72d699ba3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_01a068fb-ecbd-7628-8653-30e373405075" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilityNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_01a068fb-ecbd-7c45-9a01-40b9cdc5c80b" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_01a068fb-ecbd-7628-8653-30e373405075" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_PreTaxFairValueGainsLossesRecognizedDuringThePeriodIn_01a068fb-ecbd-78e3-abee-b5f6ecd24c70" xlink:href="sps-20260930.xsd#sps_PreTaxFairValueGainsLossesRecognizedDuringThePeriodIn"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_01a068fb-ecbd-7c45-9a01-40b9cdc5c80b" xlink:to="loc_sps_PreTaxFairValueGainsLossesRecognizedDuringThePeriodIn_01a068fb-ecbd-78e3-abee-b5f6ecd24c70" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/FairValueofFinancialAssetsandLiabilitiesRecurringFairValueMeasurementsDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#FairValueofFinancialAssetsandLiabilitiesRecurringFairValueMeasurementsDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/FairValueofFinancialAssetsandLiabilitiesRecurringFairValueMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_01a068fb-ecbd-7abd-9ac3-be80c773fe1a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_01a068fb-ecbd-7fc2-9329-037bda0a23df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_01a068fb-ecbd-7abd-9ac3-be80c773fe1a" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_01a068fb-ecbd-7fc2-9329-037bda0a23df" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_01a068fb-ecbd-783b-b9a6-db74b7212ba1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_01a068fb-ecbd-7fc2-9329-037bda0a23df" xlink:to="loc_us-gaap_HedgingDesignationAxis_01a068fb-ecbd-783b-b9a6-db74b7212ba1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-783b-b9a6-db74b7212ba1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_01a068fb-ecbd-783b-b9a6-db74b7212ba1" xlink:to="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-783b-b9a6-db74b7212ba1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-7daa-9596-8007d4ee08fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_01a068fb-ecbd-783b-b9a6-db74b7212ba1" xlink:to="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-7daa-9596-8007d4ee08fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_01a068fb-ecbd-7546-850c-cd53e1909fae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_01a068fb-ecbd-7daa-9596-8007d4ee08fc" xlink:to="loc_us-gaap_NondesignatedMember_01a068fb-ecbd-7546-850c-cd53e1909fae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a068fb-ecbd-7100-836b-1ae9f440a2be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_01a068fb-ecbd-7fc2-9329-037bda0a23df" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a068fb-ecbd-7100-836b-1ae9f440a2be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a068fb-ecbd-7100-836b-1ae9f440a2be_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a068fb-ecbd-7100-836b-1ae9f440a2be" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a068fb-ecbd-7100-836b-1ae9f440a2be_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a068fb-ecbd-7226-9194-a9d0b3a4718f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a068fb-ecbd-7100-836b-1ae9f440a2be" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a068fb-ecbd-7226-9194-a9d0b3a4718f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_01a068fb-ecbd-72e2-9037-82aeae8c60c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a068fb-ecbd-7226-9194-a9d0b3a4718f" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_01a068fb-ecbd-72e2-9037-82aeae8c60c5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_01a068fb-ecbd-7911-8c11-acaeca393b4e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a068fb-ecbd-7226-9194-a9d0b3a4718f" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_01a068fb-ecbd-7911-8c11-acaeca393b4e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_01a068fb-ecbd-715a-833f-5c1ee1a0793a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a068fb-ecbd-7226-9194-a9d0b3a4718f" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_01a068fb-ecbd-715a-833f-5c1ee1a0793a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7137-a9c8-6f277904ae32" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_01a068fb-ecbd-7fc2-9329-037bda0a23df" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7137-a9c8-6f277904ae32" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7137-a9c8-6f277904ae32_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7137-a9c8-6f277904ae32" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7137-a9c8-6f277904ae32_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7ba3-b286-efbceedbd5b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7137-a9c8-6f277904ae32" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7ba3-b286-efbceedbd5b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_ElectricCommodityContractMember_01a068fb-ecbd-7ef0-9b95-e6293e8f79b8" xlink:href="sps-20260930.xsd#sps_ElectricCommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7ba3-b286-efbceedbd5b4" xlink:to="loc_sps_ElectricCommodityContractMember_01a068fb-ecbd-7ef0-9b95-e6293e8f79b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_01a068fb-ecbd-7205-8fbb-1dda1f41cc82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7ba3-b286-efbceedbd5b4" xlink:to="loc_us-gaap_CommodityContractMember_01a068fb-ecbd-7205-8fbb-1dda1f41cc82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_CreditQualityIndicatorAxis_01a068fb-ecbd-738f-85bd-b08da07aa950" xlink:href="sps-20260930.xsd#sps_CreditQualityIndicatorAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_01a068fb-ecbd-7fc2-9329-037bda0a23df" xlink:to="loc_sps_CreditQualityIndicatorAxis_01a068fb-ecbd-738f-85bd-b08da07aa950" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_CreditQualityIndicatorDomain_01a068fb-ecbd-738f-85bd-b08da07aa950_default" xlink:href="sps-20260930.xsd#sps_CreditQualityIndicatorDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_sps_CreditQualityIndicatorAxis_01a068fb-ecbd-738f-85bd-b08da07aa950" xlink:to="loc_sps_CreditQualityIndicatorDomain_01a068fb-ecbd-738f-85bd-b08da07aa950_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_CreditQualityIndicatorDomain_01a068fb-ecbd-777f-a152-b08c79572aaa" xlink:href="sps-20260930.xsd#sps_CreditQualityIndicatorDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_sps_CreditQualityIndicatorAxis_01a068fb-ecbd-738f-85bd-b08da07aa950" xlink:to="loc_sps_CreditQualityIndicatorDomain_01a068fb-ecbd-777f-a152-b08c79572aaa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExternalCreditRatingInvestmentGradeMember_01a068fb-ecbd-7bd8-abdb-58ec9198c66c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ExternalCreditRatingInvestmentGradeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sps_CreditQualityIndicatorDomain_01a068fb-ecbd-777f-a152-b08c79572aaa" xlink:to="loc_us-gaap_ExternalCreditRatingInvestmentGradeMember_01a068fb-ecbd-7bd8-abdb-58ec9198c66c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_01a068fb-ecbd-78ca-8094-395d5990a08a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_01a068fb-ecbd-7fc2-9329-037bda0a23df" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_01a068fb-ecbd-78ca-8094-395d5990a08a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_01a068fb-ecbd-78ca-8094-395d5990a08a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_01a068fb-ecbd-78ca-8094-395d5990a08a" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_01a068fb-ecbd-78ca-8094-395d5990a08a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_01a068fb-ecbd-70d6-9ac1-f91a846c408d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_01a068fb-ecbd-78ca-8094-395d5990a08a" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_01a068fb-ecbd-70d6-9ac1-f91a846c408d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditConcentrationRiskMember_01a068fb-ecbd-72b5-ae03-abdc58ebecff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_01a068fb-ecbd-70d6-9ac1-f91a846c408d" xlink:to="loc_us-gaap_CreditConcentrationRiskMember_01a068fb-ecbd-72b5-ae03-abdc58ebecff" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_01a068fb-ecbd-7fe1-b93c-babcfbb66eb0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_01a068fb-ecbd-7fc2-9329-037bda0a23df" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_01a068fb-ecbd-7fe1-b93c-babcfbb66eb0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_01a068fb-ecbd-7fe1-b93c-babcfbb66eb0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_01a068fb-ecbd-7fe1-b93c-babcfbb66eb0" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_01a068fb-ecbd-7fe1-b93c-babcfbb66eb0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_01a068fb-ecbd-7511-9703-cd960c813751" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_01a068fb-ecbd-7fe1-b93c-babcfbb66eb0" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_01a068fb-ecbd-7511-9703-cd960c813751" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_01a068fb-ecbd-7bff-8fb1-9fc47c27db6b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_01a068fb-ecbd-7511-9703-cd960c813751" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_01a068fb-ecbd-7bff-8fb1-9fc47c27db6b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_01a068fb-ecbd-76ef-981f-b64bd8bb8457" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_01a068fb-ecbd-7abd-9ac3-be80c773fe1a" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_01a068fb-ecbd-76ef-981f-b64bd8bb8457" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetFairValueGrossLiabilityAndObligationToReturnCashOffset_01a068fb-ecbd-7869-9a4d-32d5b73dbe6d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssetFairValueGrossLiabilityAndObligationToReturnCashOffset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_01a068fb-ecbd-7abd-9ac3-be80c773fe1a" xlink:to="loc_us-gaap_DerivativeAssetFairValueGrossLiabilityAndObligationToReturnCashOffset_01a068fb-ecbd-7869-9a4d-32d5b73dbe6d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetsCurrent_01a068fb-ecbd-7c83-b27b-6c841274b3cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_01a068fb-ecbd-7abd-9ac3-be80c773fe1a" xlink:to="loc_us-gaap_DerivativeAssetsCurrent_01a068fb-ecbd-7c83-b27b-6c841274b3cb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetCollateralObligationToReturnCashOffset_01a068fb-ecbd-7a42-b193-09d69b680c5c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssetCollateralObligationToReturnCashOffset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_01a068fb-ecbd-7abd-9ac3-be80c773fe1a" xlink:to="loc_us-gaap_DerivativeAssetCollateralObligationToReturnCashOffset_01a068fb-ecbd-7a42-b193-09d69b680c5c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_01a068fb-ecbd-75fe-8a0a-6db60e7d7726" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_01a068fb-ecbd-7abd-9ac3-be80c773fe1a" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_01a068fb-ecbd-75fe-8a0a-6db60e7d7726" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs_01a068fb-ecbd-7c32-8b6f-024e8fdd1ddc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_01a068fb-ecbd-75fe-8a0a-6db60e7d7726" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs_01a068fb-ecbd-7c32-8b6f-024e8fdd1ddc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases_01a068fb-ecbd-7a0b-96c1-2988298f014c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_01a068fb-ecbd-75fe-8a0a-6db60e7d7726" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases_01a068fb-ecbd-7a0b-96c1-2988298f014c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements_01a068fb-ecbd-7fcc-9413-0f2d9f3c10f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_01a068fb-ecbd-75fe-8a0a-6db60e7d7726" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements_01a068fb-ecbd-7fcc-9413-0f2d9f3c10f5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetLiabilityNetLossesGainsRecognizedAsRegulatoryAssetsAndLiabilities_01a068fb-ecbd-722e-b48a-3546513ccddf" xlink:href="sps-20260930.xsd#sps_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetLiabilityNetLossesGainsRecognizedAsRegulatoryAssetsAndLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_01a068fb-ecbd-75fe-8a0a-6db60e7d7726" xlink:to="loc_sps_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetLiabilityNetLossesGainsRecognizedAsRegulatoryAssetsAndLiabilities_01a068fb-ecbd-722e-b48a-3546513ccddf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs_01a068fb-ecbd-7bde-8de8-6d8f72f25e1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgesAtFairValueNet_01a068fb-ecbd-7051-b8ea-74eefd1abb68" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueHedgesAtFairValueNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_01a068fb-ecbd-7abd-9ac3-be80c773fe1a" xlink:to="loc_us-gaap_FairValueHedgesAtFairValueNet_01a068fb-ecbd-7051-b8ea-74eefd1abb68" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/FairValueofFinancialAssetsandLiabilitiesFairValueofLongTermDebtDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#FairValueofFinancialAssetsandLiabilitiesFairValueofLongTermDebtDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/FairValueofFinancialAssetsandLiabilitiesFairValueofLongTermDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_01a068fb-ecbd-77aa-9ea4-8e08cdb62373" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_01a068fb-ecbd-7fdc-a6ee-f5a2d12f8336" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_01a068fb-ecbd-77aa-9ea4-8e08cdb62373" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_01a068fb-ecbd-7fdc-a6ee-f5a2d12f8336" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a068fb-ecbd-7025-9955-d4e1c122c373" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_01a068fb-ecbd-7fdc-a6ee-f5a2d12f8336" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a068fb-ecbd-7025-9955-d4e1c122c373" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a068fb-ecbd-7025-9955-d4e1c122c373_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a068fb-ecbd-7025-9955-d4e1c122c373" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a068fb-ecbd-7025-9955-d4e1c122c373_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a068fb-ecbd-7edc-90e3-444416d78101" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a068fb-ecbd-7025-9955-d4e1c122c373" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a068fb-ecbd-7edc-90e3-444416d78101" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_01a068fb-ecbd-767e-bbd0-c77301c88433" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a068fb-ecbd-7edc-90e3-444416d78101" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_01a068fb-ecbd-767e-bbd0-c77301c88433" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ecbd-7a43-948b-4641d9cb613e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_01a068fb-ecbd-7fdc-a6ee-f5a2d12f8336" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ecbd-7a43-948b-4641d9cb613e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a068fb-ecbd-7a43-948b-4641d9cb613e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ecbd-7a43-948b-4641d9cb613e" xlink:to="loc_us-gaap_RelatedPartyDomain_01a068fb-ecbd-7a43-948b-4641d9cb613e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a068fb-ecbd-7d29-b318-6eae71814e75" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a068fb-ecbd-7a43-948b-4641d9cb613e" xlink:to="loc_us-gaap_RelatedPartyDomain_01a068fb-ecbd-7d29-b318-6eae71814e75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_01a068fb-ecbd-7c8e-8fa8-d9a407f1a7f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a068fb-ecbd-7d29-b318-6eae71814e75" xlink:to="loc_us-gaap_RelatedPartyMember_01a068fb-ecbd-7c8e-8fa8-d9a407f1a7f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_01a068fb-ecbd-72cd-87f2-0bb49024b717" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_01a068fb-ecbd-77aa-9ea4-8e08cdb62373" xlink:to="loc_us-gaap_LongTermDebt_01a068fb-ecbd-72cd-87f2-0bb49024b717" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_01a068fb-ecbd-763b-85eb-3f5759e9606d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_01a068fb-ecbd-77aa-9ea4-8e08cdb62373" xlink:to="loc_us-gaap_LongTermDebtFairValue_01a068fb-ecbd-763b-85eb-3f5759e9606d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_01a068fb-ecbd-7c3e-be8e-9176d105dc4a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_01a068fb-ecbd-77aa-9ea4-8e08cdb62373" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_01a068fb-ecbd-7c3e-be8e-9176d105dc4a" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/FairValueofFinancialAssetsandLiabilitiesInterestRateDerivativesDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#FairValueofFinancialAssetsandLiabilitiesInterestRateDerivativesDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/FairValueofFinancialAssetsandLiabilitiesInterestRateDerivativesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-73d0-9652-00345c602f35" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_01a068fb-ecbd-710c-b18f-90c387bccc3e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-73d0-9652-00345c602f35" xlink:to="loc_us-gaap_DerivativeTable_01a068fb-ecbd-710c-b18f-90c387bccc3e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7f03-b587-4ed96e571f03" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_01a068fb-ecbd-710c-b18f-90c387bccc3e" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7f03-b587-4ed96e571f03" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7f03-b587-4ed96e571f03_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7f03-b587-4ed96e571f03" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7f03-b587-4ed96e571f03_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7b98-9a1c-9ec1ee8a04c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a068fb-ecbd-7f03-b587-4ed96e571f03" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7b98-9a1c-9ec1ee8a04c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_01a068fb-ecbd-7f02-9e93-39d3f210978c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_01a068fb-ecbd-7b98-9a1c-9ec1ee8a04c2" xlink:to="loc_us-gaap_InterestRateSwapMember_01a068fb-ecbd-7f02-9e93-39d3f210978c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_01a068fb-ecbd-78c9-a17f-d332330eac95" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilityNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-73d0-9652-00345c602f35" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_01a068fb-ecbd-78c9-a17f-d332330eac95" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet_01a068fb-ecbd-7ecd-8a4e-a2817ed4b037" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a068fb-ecbd-73d0-9652-00345c602f35" xlink:to="loc_us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet_01a068fb-ecbd-7ecd-8a4e-a2817ed4b037" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/BenefitPlansandOtherPostretirementBenefitsDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#BenefitPlansandOtherPostretirementBenefitsDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/BenefitPlansandOtherPostretirementBenefitsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_01a068fb-ecbd-79fa-b0da-39756bb637bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_01a068fb-ecbd-7110-9839-de1fbe29adeb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_01a068fb-ecbd-79fa-b0da-39756bb637bf" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_01a068fb-ecbd-7110-9839-de1fbe29adeb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_01a068fb-ecbd-7da1-9b6d-35d48f0447fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_01a068fb-ecbd-7110-9839-de1fbe29adeb" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_01a068fb-ecbd-7da1-9b6d-35d48f0447fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_01a068fb-ecbd-7da1-9b6d-35d48f0447fd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_01a068fb-ecbd-7da1-9b6d-35d48f0447fd" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_01a068fb-ecbd-7da1-9b6d-35d48f0447fd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_01a068fb-ecbd-72f9-ac48-80c14fae5cb5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_01a068fb-ecbd-7da1-9b6d-35d48f0447fd" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_01a068fb-ecbd-72f9-ac48-80c14fae5cb5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_01a068fb-ecbd-7ccc-8ae2-9e1ac29571d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_01a068fb-ecbd-72f9-ac48-80c14fae5cb5" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_01a068fb-ecbd-7ccc-8ae2-9e1ac29571d0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_01a068fb-ecbd-7e5a-a331-fd294f7ffdc0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_01a068fb-ecbd-7110-9839-de1fbe29adeb" xlink:to="loc_srt_ConsolidatedEntitiesAxis_01a068fb-ecbd-7e5a-a331-fd294f7ffdc0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_01a068fb-ecbd-7e5a-a331-fd294f7ffdc0_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_01a068fb-ecbd-7e5a-a331-fd294f7ffdc0" xlink:to="loc_srt_ConsolidatedEntitiesDomain_01a068fb-ecbd-7e5a-a331-fd294f7ffdc0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_01a068fb-ecbd-7c1a-9616-f285137aa6c4" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_01a068fb-ecbd-7e5a-a331-fd294f7ffdc0" xlink:to="loc_srt_ConsolidatedEntitiesDomain_01a068fb-ecbd-7c1a-9616-f285137aa6c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ParentCompanyMember_01a068fb-ecbd-7f31-93a1-152a9d966cd0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ParentCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_01a068fb-ecbd-7c1a-9616-f285137aa6c4" xlink:to="loc_srt_ParentCompanyMember_01a068fb-ecbd-7f31-93a1-152a9d966cd0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_01a068fb-ecbd-7e71-90e6-a1c3ff3aa0b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_01a068fb-ecbd-79fa-b0da-39756bb637bf" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_01a068fb-ecbd-7e71-90e6-a1c3ff3aa0b0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_01a068fb-ecbd-73bd-8940-ca2359086b24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_01a068fb-ecbd-7e71-90e6-a1c3ff3aa0b0" xlink:to="loc_us-gaap_DefinedBenefitPlanServiceCost_01a068fb-ecbd-73bd-8940-ca2359086b24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_01a068fb-ecbd-79a1-a964-27a65d0a0587" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_01a068fb-ecbd-7e71-90e6-a1c3ff3aa0b0" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_01a068fb-ecbd-79a1-a964-27a65d0a0587" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_01a068fb-ecbd-749f-9a16-2bbdced31837" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_01a068fb-ecbd-7e71-90e6-a1c3ff3aa0b0" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_01a068fb-ecbd-749f-9a16-2bbdced31837" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_01a068fb-ecbd-70e1-b666-23195ebc1968" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_01a068fb-ecbd-7e71-90e6-a1c3ff3aa0b0" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_01a068fb-ecbd-70e1-b666-23195ebc1968" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_DefinedBenefitPlanNetBenefitCostCreditRecognizedBeforeRegulatoryAdjustments_01a068fb-ecbd-7cb5-9352-d62d0b6b01a2" xlink:href="sps-20260930.xsd#sps_DefinedBenefitPlanNetBenefitCostCreditRecognizedBeforeRegulatoryAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_01a068fb-ecbd-7e71-90e6-a1c3ff3aa0b0" xlink:to="loc_sps_DefinedBenefitPlanNetBenefitCostCreditRecognizedBeforeRegulatoryAdjustments_01a068fb-ecbd-7cb5-9352-d62d0b6b01a2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionContributions_01a068fb-ecbd-7f00-829b-cbc227c497d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PensionContributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_01a068fb-ecbd-79fa-b0da-39756bb637bf" xlink:to="loc_us-gaap_PensionContributions_01a068fb-ecbd-7f00-829b-cbc227c497d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_DefinedBenefitPlanCreditsNotRecognizedDueToEffectsofRegulation_01a068fb-ecbd-7cad-8997-fd9a87efc410" xlink:href="sps-20260930.xsd#sps_DefinedBenefitPlanCreditsNotRecognizedDueToEffectsofRegulation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_01a068fb-ecbd-79fa-b0da-39756bb637bf" xlink:to="loc_sps_DefinedBenefitPlanCreditsNotRecognizedDueToEffectsofRegulation_01a068fb-ecbd-7cad-8997-fd9a87efc410" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_01a068fb-ecbd-7ab4-99eb-98a7ab955c83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_01a068fb-ecbd-79fa-b0da-39756bb637bf" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_01a068fb-ecbd-7ab4-99eb-98a7ab955c83" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/CommitmentsandContingenciesEnvironmentalDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#CommitmentsandContingenciesEnvironmentalDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/CommitmentsandContingenciesEnvironmentalDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_01a068fb-ecbd-7c69-9477-7eb07b01011f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_01a068fb-ecbd-7347-8b90-46e790d8a412" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_01a068fb-ecbd-7c69-9477-7eb07b01011f" xlink:to="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_01a068fb-ecbd-7347-8b90-46e790d8a412" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnvironmentalRemediationSiteAxis_01a068fb-ecbd-7043-9d28-d27eea517bb0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EnvironmentalRemediationSiteAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_01a068fb-ecbd-7347-8b90-46e790d8a412" xlink:to="loc_us-gaap_EnvironmentalRemediationSiteAxis_01a068fb-ecbd-7043-9d28-d27eea517bb0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnvironmentalRemediationSiteDomain_01a068fb-ecbd-7043-9d28-d27eea517bb0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EnvironmentalRemediationSiteDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EnvironmentalRemediationSiteAxis_01a068fb-ecbd-7043-9d28-d27eea517bb0" xlink:to="loc_us-gaap_EnvironmentalRemediationSiteDomain_01a068fb-ecbd-7043-9d28-d27eea517bb0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnvironmentalRemediationSiteDomain_01a068fb-ecbd-74a2-b03a-182abcab6efe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EnvironmentalRemediationSiteDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EnvironmentalRemediationSiteAxis_01a068fb-ecbd-7043-9d28-d27eea517bb0" xlink:to="loc_us-gaap_EnvironmentalRemediationSiteDomain_01a068fb-ecbd-74a2-b03a-182abcab6efe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_OtherMGPLandfillOrDisposalSitesMember_01a068fb-ecbd-7ce5-acf1-afe36b129037" xlink:href="sps-20260930.xsd#sps_OtherMGPLandfillOrDisposalSitesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EnvironmentalRemediationSiteDomain_01a068fb-ecbd-74a2-b03a-182abcab6efe" xlink:to="loc_sps_OtherMGPLandfillOrDisposalSitesMember_01a068fb-ecbd-7ce5-acf1-afe36b129037" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_NumberofidentifiedMGPlandfillordisposalsitesundercurrentinvestigationandorremediation_01a068fb-ecbd-7ea0-9e35-27c2c0d5b87a" xlink:href="sps-20260930.xsd#sps_NumberofidentifiedMGPlandfillordisposalsitesundercurrentinvestigationandorremediation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_01a068fb-ecbd-7c69-9477-7eb07b01011f" xlink:to="loc_sps_NumberofidentifiedMGPlandfillordisposalsitesundercurrentinvestigationandorremediation_01a068fb-ecbd-7ea0-9e35-27c2c0d5b87a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/LeasesDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#LeasesDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/LeasesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_01a068fb-ecbd-7b96-aa68-cbb67a361325" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_01a068fb-ecbd-7852-8272-0e378a328b69" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_01a068fb-ecbd-7b96-aa68-cbb67a361325" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_01a068fb-ecbd-7852-8272-0e378a328b69" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a068fb-ecbd-7a5d-879b-11d70bc14062" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_01a068fb-ecbd-7852-8272-0e378a328b69" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a068fb-ecbd-7a5d-879b-11d70bc14062" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a068fb-ecbd-7a5d-879b-11d70bc14062_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a068fb-ecbd-7a5d-879b-11d70bc14062" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a068fb-ecbd-7a5d-879b-11d70bc14062_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a068fb-ecbd-7c00-83a9-8c0a268dd127" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a068fb-ecbd-7a5d-879b-11d70bc14062" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a068fb-ecbd-7c00-83a9-8c0a268dd127" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_PurchasedPowerAgreementsMember_01a068fb-ecbd-7149-ac46-880f15d5324d" xlink:href="sps-20260930.xsd#sps_PurchasedPowerAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a068fb-ecbd-7c00-83a9-8c0a268dd127" xlink:to="loc_sps_PurchasedPowerAgreementsMember_01a068fb-ecbd-7149-ac46-880f15d5324d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentOtherTypesMember_01a068fb-ecbd-7fa2-8687-71039ef9695d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentOtherTypesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a068fb-ecbd-7c00-83a9-8c0a268dd127" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentOtherTypesMember_01a068fb-ecbd-7fa2-8687-71039ef9695d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseCost_01a068fb-ecbd-7fdd-86a4-09569c8debb2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_01a068fb-ecbd-7b96-aa68-cbb67a361325" xlink:to="loc_us-gaap_OperatingLeaseCost_01a068fb-ecbd-7fdd-86a4-09569c8debb2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_01a068fb-ecbd-72de-8aec-85655210c88e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_01a068fb-ecbd-7b96-aa68-cbb67a361325" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_01a068fb-ecbd-72de-8aec-85655210c88e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_01a068fb-ecbe-7d74-883b-a7c305b8511e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_01a068fb-ecbd-7b96-aa68-cbb67a361325" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_01a068fb-ecbe-7d74-883b-a7c305b8511e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_01a068fb-ecbe-7756-83d0-2546f9672d6a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_01a068fb-ecbd-7b96-aa68-cbb67a361325" xlink:to="loc_us-gaap_OperatingLeaseLiability_01a068fb-ecbe-7756-83d0-2546f9672d6a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_01a068fb-ecbe-7676-a6a6-ce370a0e5a62" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_01a068fb-ecbd-7b96-aa68-cbb67a361325" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_01a068fb-ecbe-7676-a6a6-ce370a0e5a62" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_01a068fb-ecbe-7f08-8cef-daed6792e1d9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_01a068fb-ecbd-7b96-aa68-cbb67a361325" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_01a068fb-ecbe-7f08-8cef-daed6792e1d9" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/CommitmentsandContingenciesVariableInterestEntitiesDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#CommitmentsandContingenciesVariableInterestEntitiesDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/CommitmentsandContingenciesVariableInterestEntitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_01a068fb-ecbe-786d-a01b-2303a520cdc5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableInterestEntityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_01a068fb-ecbe-7fb9-9d0d-3d6e47500be3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_01a068fb-ecbe-786d-a01b-2303a520cdc5" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_01a068fb-ecbe-7fb9-9d0d-3d6e47500be3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_01a068fb-ecbe-7fc3-b1f6-272f00473fdd" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_01a068fb-ecbe-7fb9-9d0d-3d6e47500be3" xlink:to="loc_srt_ConsolidatedEntitiesAxis_01a068fb-ecbe-7fc3-b1f6-272f00473fdd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_01a068fb-ecbe-7fc3-b1f6-272f00473fdd_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_01a068fb-ecbe-7fc3-b1f6-272f00473fdd" xlink:to="loc_srt_ConsolidatedEntitiesDomain_01a068fb-ecbe-7fc3-b1f6-272f00473fdd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_01a068fb-ecbe-722c-b3d2-1e130124d0b6" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_01a068fb-ecbe-7fc3-b1f6-272f00473fdd" xlink:to="loc_srt_ConsolidatedEntitiesDomain_01a068fb-ecbe-722c-b3d2-1e130124d0b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember_01a068fb-ecbe-7fd6-8fe0-c69c6fc05209" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_01a068fb-ecbe-722c-b3d2-1e130124d0b6" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember_01a068fb-ecbe-7fd6-8fe0-c69c6fc05209" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_01a068fb-ecbe-7349-a3ac-e2d51a47ba22" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_01a068fb-ecbe-7349-a3ac-e2d51a47ba22_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_01a068fb-ecbe-7059-a0e8-b7ade81b2f4c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember_01a068fb-ecbe-76c3-820e-78158f66e1a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_PurchasedPowerAgreementsAbstract_01a068fb-ecbe-79f5-8e39-be5281a2fcab" xlink:href="sps-20260930.xsd#sps_PurchasedPowerAgreementsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_01a068fb-ecbe-786d-a01b-2303a520cdc5" xlink:to="loc_sps_PurchasedPowerAgreementsAbstract_01a068fb-ecbe-79f5-8e39-be5281a2fcab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_GeneratingCapacityUnderLongTermPurchasedPowerAgreements_01a068fb-ecbe-7d3f-b09c-39ecdbfa0d79" xlink:href="sps-20260930.xsd#sps_GeneratingCapacityUnderLongTermPurchasedPowerAgreements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sps_PurchasedPowerAgreementsAbstract_01a068fb-ecbe-79f5-8e39-be5281a2fcab" xlink:to="loc_sps_GeneratingCapacityUnderLongTermPurchasedPowerAgreements_01a068fb-ecbe-7d3f-b09c-39ecdbfa0d79" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.xcelenergy.com/role/SegmentReportingDetails" xlink:type="simple" xlink:href="sps-20260930.xsd#SegmentReportingDetails"/>
  <link:definitionLink xlink:role="http://www.xcelenergy.com/role/SegmentReportingDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_01a068fb-ecbe-7b95-9d25-3c964be1bae2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a068fb-ecbe-7370-8d56-62fb5c82a790" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a068fb-ecbe-7b95-9d25-3c964be1bae2" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a068fb-ecbe-7370-8d56-62fb5c82a790" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_01a068fb-ecbe-7561-a08f-3e3af407e62c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a068fb-ecbe-7370-8d56-62fb5c82a790" xlink:to="loc_srt_ConsolidationItemsAxis_01a068fb-ecbe-7561-a08f-3e3af407e62c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_01a068fb-ecbe-7561-a08f-3e3af407e62c_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_01a068fb-ecbe-7561-a08f-3e3af407e62c" xlink:to="loc_srt_ConsolidationItemsDomain_01a068fb-ecbe-7561-a08f-3e3af407e62c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_01a068fb-ecbe-7019-b844-4e1a24324c7e" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_01a068fb-ecbe-7561-a08f-3e3af407e62c" xlink:to="loc_srt_ConsolidationItemsDomain_01a068fb-ecbe-7019-b844-4e1a24324c7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_01a068fb-ecbe-70cb-95a6-0a879b207ecd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_01a068fb-ecbe-7019-b844-4e1a24324c7e" xlink:to="loc_us-gaap_OperatingSegmentsMember_01a068fb-ecbe-70cb-95a6-0a879b207ecd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_01a068fb-ecbe-7543-a9a3-806052f6f3bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a068fb-ecbe-7370-8d56-62fb5c82a790" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_01a068fb-ecbe-7543-a9a3-806052f6f3bb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_01a068fb-ecbe-7543-a9a3-806052f6f3bb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01a068fb-ecbe-7543-a9a3-806052f6f3bb" xlink:to="loc_us-gaap_SegmentDomain_01a068fb-ecbe-7543-a9a3-806052f6f3bb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_01a068fb-ecbe-7ed2-abd6-8ab54788430e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01a068fb-ecbe-7543-a9a3-806052f6f3bb" xlink:to="loc_us-gaap_SegmentDomain_01a068fb-ecbe-7ed2-abd6-8ab54788430e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_RegulatedElectricSegmentMember_01a068fb-ecbe-7dd3-9a66-f4fad957d6d2" xlink:href="sps-20260930.xsd#sps_RegulatedElectricSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_01a068fb-ecbe-7ed2-abd6-8ab54788430e" xlink:to="loc_sps_RegulatedElectricSegmentMember_01a068fb-ecbe-7dd3-9a66-f4fad957d6d2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_RegulatedOperatingRevenueElectric_01a068fb-ecbe-7984-9475-017e66fba1e5" xlink:href="sps-20260930.xsd#sps_RegulatedOperatingRevenueElectric"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a068fb-ecbe-7b95-9d25-3c964be1bae2" xlink:to="loc_sps_RegulatedOperatingRevenueElectric_01a068fb-ecbe-7984-9475-017e66fba1e5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_ElectricFuelandPurchasedPower_01a068fb-ecbe-756d-a408-312ff39a20fe" xlink:href="sps-20260930.xsd#sps_ElectricFuelandPurchasedPower"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a068fb-ecbe-7b95-9d25-3c964be1bae2" xlink:to="loc_sps_ElectricFuelandPurchasedPower_01a068fb-ecbe-756d-a408-312ff39a20fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses_01a068fb-ecbe-7f2c-ab32-227d86c0f0a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a068fb-ecbe-7b95-9d25-3c964be1bae2" xlink:to="loc_us-gaap_UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses_01a068fb-ecbe-7f2c-ab32-227d86c0f0a5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization_01a068fb-ecbe-7342-8887-553fd79860eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a068fb-ecbe-7b95-9d25-3c964be1bae2" xlink:to="loc_us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization_01a068fb-ecbe-7342-8887-553fd79860eb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_01a068fb-ecbe-7b13-af6f-fdacadb5567c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a068fb-ecbe-7b95-9d25-3c964be1bae2" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_01a068fb-ecbe-7b13-af6f-fdacadb5567c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndDebtExpense_01a068fb-ecbe-7bda-8a32-db93e3735daa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestAndDebtExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a068fb-ecbe-7b95-9d25-3c964be1bae2" xlink:to="loc_us-gaap_InterestAndDebtExpense_01a068fb-ecbe-7bda-8a32-db93e3735daa" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_01a068fb-ecbe-7031-8568-39b7dad35aa8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a068fb-ecbe-7b95-9d25-3c964be1bae2" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_01a068fb-ecbe-7031-8568-39b7dad35aa8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_01a068fb-ecbe-74cc-8053-a62664ea5322" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a068fb-ecbe-7b95-9d25-3c964be1bae2" xlink:to="loc_us-gaap_NetIncomeLoss_01a068fb-ecbe-74cc-8053-a62664ea5322" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_sps_NumberOfReportableSegmentsDisclosedByDefinitionFlag_01a068fb-ecbe-7ca8-bdb3-06e6f130cfe7" xlink:href="sps-20260930.xsd#sps_NumberOfReportableSegmentsDisclosedByDefinitionFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a068fb-ecbe-7b95-9d25-3c964be1bae2" xlink:to="loc_sps_NumberOfReportableSegmentsDisclosedByDefinitionFlag_01a068fb-ecbe-7ca8-bdb3-06e6f130cfe7" xlink:type="arc" order="8"/>
  </link:definitionLink>
</link:linkbase>
