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    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_ArizonaRenewableEnergyStandardAndTariffAnnualImplementationPlan2014To2018Member" xlink:label="loc_pnw_ArizonaRenewableEnergyStandardAndTariffAnnualImplementationPlan2014To2018Member" xlink:title="ArizonaRenewableEnergyStandardAndTariffAnnualImplementationPlan2014To2018Member" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain" xlink:to="loc_pnw_ArizonaRenewableEnergyStandardAndTariffAnnualImplementationPlan2014To2018Member" xlink:title="Definition : loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain to loc_pnw_ArizonaRenewableEnergyStandardAndTariffAnnualImplementationPlan2014To2018Member" xlink:type="arc" use="optional" order="4" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_pnw_RegulatoryMattersLineItems" xlink:to="loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract" xlink:title="Definition : loc_pnw_RegulatoryMattersLineItems to loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract" xlink:type="arc" use="optional" order="4" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_RateMatterBaseFuelRateCurrent" xlink:label="loc_pnw_RateMatterBaseFuelRateCurrent" xlink:title="RateMatterBaseFuelRateCurrent" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract" xlink:to="loc_pnw_RateMatterBaseFuelRateCurrent" xlink:title="Definition : loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract to loc_pnw_RateMatterBaseFuelRateCurrent" xlink:type="arc" use="optional" order="4" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_RateMatterApprovedBudget" xlink:label="loc_pnw_RateMatterApprovedBudget" xlink:title="RateMatterApprovedBudget" />
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    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_pnw_ScheduleOfRegulatoryMattersTable" xlink:to="loc_pnw_YearOfRateCasesAxis" xlink:title="Definition : loc_pnw_ScheduleOfRegulatoryMattersTable to loc_pnw_YearOfRateCasesAxis" xlink:type="arc" use="optional" order="4" />
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    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_pnw_ScheduleOfRegulatoryMattersTable" xlink:to="loc_us-gaap_RangeAxis" xlink:title="Definition : loc_pnw_ScheduleOfRegulatoryMattersTable to loc_us-gaap_RangeAxis" xlink:type="arc" use="optional" order="6" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_OpenAccessTransmissionTariffMember" xlink:label="loc_pnw_OpenAccessTransmissionTariffMember" xlink:title="OpenAccessTransmissionTariffMember" />
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    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_PSARateInPriorYears" xlink:label="loc_pnw_PSARateInPriorYears" xlink:title="PSARateInPriorYears" />
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    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInRegulatoryClauseRevenue" xlink:label="loc_us-gaap_IncreaseDecreaseInRegulatoryClauseRevenue" xlink:title="IncreaseDecreaseInRegulatoryClauseRevenue" />
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    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_LostFixedCostRecoveryMechanismsMember" xlink:label="loc_pnw_LostFixedCostRecoveryMechanismsMember" xlink:title="LostFixedCostRecoveryMechanismsMember" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain" xlink:to="loc_pnw_LostFixedCostRecoveryMechanismsMember" xlink:title="Definition : loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain to loc_pnw_LostFixedCostRecoveryMechanismsMember" xlink:type="arc" use="optional" order="8" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PublicUtilitiesApprovedDebtCapitalStructurePercentage" xlink:label="loc_us-gaap_PublicUtilitiesApprovedDebtCapitalStructurePercentage" xlink:title="PublicUtilitiesApprovedDebtCapitalStructurePercentage" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract" xlink:to="loc_us-gaap_PublicUtilitiesApprovedDebtCapitalStructurePercentage" xlink:title="Definition : loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract to loc_us-gaap_PublicUtilitiesApprovedDebtCapitalStructurePercentage" xlink:type="arc" use="optional" order="8" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_ForwardComponentOfPSARate" xlink:label="loc_pnw_ForwardComponentOfPSARate" xlink:title="ForwardComponentOfPSARate" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_pnw_RegulatoryMattersLineItems" xlink:to="loc_pnw_ForwardComponentOfPSARate" xlink:title="Definition : loc_pnw_RegulatoryMattersLineItems to loc_pnw_ForwardComponentOfPSARate" xlink:type="arc" use="optional" order="8" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_IncreaseDecreaseDeferredFuelAndPurchasedPowerAmortization" xlink:label="loc_pnw_IncreaseDecreaseDeferredFuelAndPurchasedPowerAmortization" xlink:title="IncreaseDecreaseDeferredFuelAndPurchasedPowerAmortization" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_pnw_DeferredFuelAndPurchasedPowerRegulatoryAssetLiabilityRollForward" xlink:to="loc_pnw_IncreaseDecreaseDeferredFuelAndPurchasedPowerAmortization" xlink:title="Definition : loc_pnw_DeferredFuelAndPurchasedPowerRegulatoryAssetLiabilityRollForward to loc_pnw_IncreaseDecreaseDeferredFuelAndPurchasedPowerAmortization" xlink:type="arc" use="optional" order="8" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage" xlink:label="loc_us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage" xlink:title="PublicUtilitiesApprovedEquityCapitalStructurePercentage" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract" xlink:to="loc_us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage" xlink:title="Definition : loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract to loc_us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage" xlink:type="arc" use="optional" order="9" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_HistoricalComponentOfPSARate" xlink:label="loc_pnw_HistoricalComponentOfPSARate" xlink:title="HistoricalComponentOfPSARate" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_pnw_RegulatoryMattersLineItems" xlink:to="loc_pnw_HistoricalComponentOfPSARate" xlink:title="Definition : loc_pnw_RegulatoryMattersLineItems to loc_pnw_HistoricalComponentOfPSARate" xlink:type="arc" use="optional" order="9" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_ArizonaRenewableEnergyStandardAndTariff2014Member" xlink:label="loc_pnw_ArizonaRenewableEnergyStandardAndTariff2014Member" xlink:title="ArizonaRenewableEnergyStandardAndTariff2014Member" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain" xlink:to="loc_pnw_ArizonaRenewableEnergyStandardAndTariff2014Member" xlink:title="Definition : loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain to loc_pnw_ArizonaRenewableEnergyStandardAndTariff2014Member" xlink:type="arc" use="optional" order="9" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_RateMatterChargeOnFutureCustomersWhoInstallRooftopSolarPanels" xlink:label="loc_pnw_RateMatterChargeOnFutureCustomersWhoInstallRooftopSolarPanels" xlink:title="RateMatterChargeOnFutureCustomersWhoInstallRooftopSolarPanels" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_pnw_DeferredFuelAndPurchasedPowerRegulatoryAssetLiabilityRollForward" xlink:to="loc_pnw_RateMatterChargeOnFutureCustomersWhoInstallRooftopSolarPanels" xlink:title="Definition : loc_pnw_DeferredFuelAndPurchasedPowerRegulatoryAssetLiabilityRollForward to loc_pnw_RateMatterChargeOnFutureCustomersWhoInstallRooftopSolarPanels" xlink:type="arc" use="optional" order="9" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_RateMatterEstimatedMonthlyCollectionDueToChargeOnFutureCustomersWhoInstallRooftopSolarPanels" xlink:label="loc_pnw_RateMatterEstimatedMonthlyCollectionDueToChargeOnFutureCustomersWhoInstallRooftopSolarPanels" xlink:title="RateMatterEstimatedMonthlyCollectionDueToChargeOnFutureCustomersWhoInstallRooftopSolarPanels" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_pnw_DeferredFuelAndPurchasedPowerRegulatoryAssetLiabilityRollForward" xlink:to="loc_pnw_RateMatterEstimatedMonthlyCollectionDueToChargeOnFutureCustomersWhoInstallRooftopSolarPanels" xlink:title="Definition : loc_pnw_DeferredFuelAndPurchasedPowerRegulatoryAssetLiabilityRollForward to loc_pnw_RateMatterEstimatedMonthlyCollectionDueToChargeOnFutureCustomersWhoInstallRooftopSolarPanels" xlink:type="arc" use="optional" order="10" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearOne" xlink:label="loc_pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearOne" xlink:title="SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearOne" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract" xlink:to="loc_pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearOne" xlink:title="Definition : loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract to loc_pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearOne" xlink:type="arc" use="optional" order="10" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_RateMattersIncreaseInCostRecovery" xlink:label="loc_pnw_RateMattersIncreaseInCostRecovery" xlink:title="RateMattersIncreaseInCostRecovery" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_pnw_RegulatoryMattersLineItems" xlink:to="loc_pnw_RateMattersIncreaseInCostRecovery" xlink:title="Definition : loc_pnw_RegulatoryMattersLineItems to loc_pnw_RateMattersIncreaseInCostRecovery" xlink:type="arc" use="optional" order="10" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearTwo" xlink:label="loc_pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearTwo" xlink:title="SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearTwo" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract" xlink:to="loc_pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearTwo" xlink:title="Definition : loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract to loc_pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearTwo" xlink:type="arc" use="optional" order="11" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_RateMatterFixedCostRecoverablePerResidentialPowerLost" xlink:label="loc_pnw_RateMatterFixedCostRecoverablePerResidentialPowerLost" xlink:title="RateMatterFixedCostRecoverablePerResidentialPowerLost" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_pnw_RegulatoryMattersLineItems" xlink:to="loc_pnw_RateMatterFixedCostRecoverablePerResidentialPowerLost" xlink:title="Definition : loc_pnw_RegulatoryMattersLineItems to loc_pnw_RateMatterFixedCostRecoverablePerResidentialPowerLost" xlink:type="arc" use="optional" order="11" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearThreeAndThereafter" xlink:label="loc_pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearThreeAndThereafter" xlink:title="SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearThreeAndThereafter" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract" xlink:to="loc_pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearThreeAndThereafter" xlink:title="Definition : loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract to loc_pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesIncreaseYearThreeAndThereafter" xlink:type="arc" use="optional" order="12" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_RateMatterFixedCostRecoverablePerNonResidentialPowerLost" xlink:label="loc_pnw_RateMatterFixedCostRecoverablePerNonResidentialPowerLost" xlink:title="RateMatterFixedCostRecoverablePerNonResidentialPowerLost" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_pnw_RegulatoryMattersLineItems" xlink:to="loc_pnw_RateMatterFixedCostRecoverablePerNonResidentialPowerLost" xlink:title="Definition : loc_pnw_RegulatoryMattersLineItems to loc_pnw_RateMatterFixedCostRecoverablePerNonResidentialPowerLost" xlink:type="arc" use="optional" order="12" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesDecrease" xlink:label="loc_pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesDecrease" xlink:title="SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesDecrease" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract" xlink:to="loc_pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesDecrease" xlink:title="Definition : loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract to loc_pnw_SettlementAgreementPercentageOfDeferralOfPropertyTaxesIfArizonaPropertyTaxRatesDecrease" xlink:type="arc" use="optional" order="13" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_RateMatterCapPercentageOfRetailRevenue" xlink:label="loc_pnw_RateMatterCapPercentageOfRetailRevenue" xlink:title="RateMatterCapPercentageOfRetailRevenue" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_pnw_RegulatoryMattersLineItems" xlink:to="loc_pnw_RateMatterCapPercentageOfRetailRevenue" xlink:title="Definition : loc_pnw_RegulatoryMattersLineItems to loc_pnw_RateMatterCapPercentageOfRetailRevenue" xlink:type="arc" use="optional" order="13" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_AmountOfAdjustmentRepresentingProratedSalesLossesApproved" xlink:label="loc_pnw_AmountOfAdjustmentRepresentingProratedSalesLossesApproved" xlink:title="AmountOfAdjustmentRepresentingProratedSalesLossesApproved" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_pnw_RegulatoryMattersLineItems" xlink:to="loc_pnw_AmountOfAdjustmentRepresentingProratedSalesLossesApproved" xlink:title="Definition : loc_pnw_RegulatoryMattersLineItems to loc_pnw_AmountOfAdjustmentRepresentingProratedSalesLossesApproved" xlink:type="arc" use="optional" order="14" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_RateMatterApproximatePercentageOfIncreaseInAverageRetailCustomerBillForSpecificTransaction" xlink:label="loc_pnw_RateMatterApproximatePercentageOfIncreaseInAverageRetailCustomerBillForSpecificTransaction" xlink:title="RateMatterApproximatePercentageOfIncreaseInAverageRetailCustomerBillForSpecificTransaction" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract" xlink:to="loc_pnw_RateMatterApproximatePercentageOfIncreaseInAverageRetailCustomerBillForSpecificTransaction" xlink:title="Definition : loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract to loc_pnw_RateMatterApproximatePercentageOfIncreaseInAverageRetailCustomerBillForSpecificTransaction" xlink:type="arc" use="optional" order="14" />
    <link:loc xlink:type="locator" xlink:href="pnw-20140630.xsd#pnw_SettlementAgreementModificationsToEISCostRecovery" xlink:label="loc_pnw_SettlementAgreementModificationsToEISCostRecovery" xlink:title="SettlementAgreementModificationsToEISCostRecovery" />
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract" xlink:to="loc_pnw_SettlementAgreementModificationsToEISCostRecovery" xlink:title="Definition : loc_us-gaap_PublicUtilitiesRateMattersApprovedAbstract to loc_pnw_SettlementAgreementModificationsToEISCostRecovery" xlink:type="arc" use="optional" order="15" />
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    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable" xlink:to="loc_us-gaap_DebtInstrumentAxis" xlink:title="Definition : loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable to loc_us-gaap_DebtInstrumentAxis" xlink:type="arc" use="optional" order="5" />
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    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis" xlink:label="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis" xlink:title="UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis" />
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    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_pnw_PowerOutageAbstract" xlink:to="loc_pnw_ReliabilityStandardRequirementsNumberNeitherAdmittedNorDeniedViolationsInSettlement" xlink:title="Definition : loc_pnw_PowerOutageAbstract to loc_pnw_ReliabilityStandardRequirementsNumberNeitherAdmittedNorDeniedViolationsInSettlement" xlink:type="arc" use="optional" order="8" />
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