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  <xs:element id="powl_LesseeAssetsAndLiabilitiesTableTextBlock" abstract="false" name="LesseeAssetsAndLiabilitiesTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="powl_LetterOfCreditCollateralAmountMinimumOutstanding" abstract="false" name="LetterOfCreditCollateralAmountMinimumOutstanding" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="powl_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" abstract="false" name="LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="powl_PercentageOfDomesticCapitalStockPledgedAsCollateralForCreditFacility" abstract="false" name="PercentageOfDomesticCapitalStockPledgedAsCollateralForCreditFacility" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="powl_DebtInstrumentCovenantInterestCoverageRatioMinimum" abstract="false" name="DebtInstrumentCovenantInterestCoverageRatioMinimum" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="powl_IndustrialDevelopmentRevenueBondsMember" abstract="true" name="IndustrialDevelopmentRevenueBondsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_FacilityAgreementMember" abstract="true" name="FacilityAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_LineOfCreditFacilityCollateralAmount" abstract="false" name="LineOfCreditFacilityCollateralAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="powl_PerformanceBasedRestrictedStockUnitMember" abstract="true" name="PerformanceBasedRestrictedStockUnitMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_ContractWithCustomerAssetLiabilityNetCurrent" abstract="false" name="ContractWithCustomerAssetLiabilityNetCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="powl_PetrochemicalMember" abstract="true" name="PetrochemicalMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_DebtInstrumentCovenantLeverageRatioMaximumAllowed" abstract="false" name="DebtInstrumentCovenantLeverageRatioMaximumAllowed" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="powl_LeaseAssetsAbstractAbstract" abstract="true" name="LeaseAssetsAbstractAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="powl_IncreaseDecreaseInContractWithCustomerAssetAndLiabilityNet" abstract="false" name="IncreaseDecreaseInContractWithCustomerAssetAndLiabilityNet" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="powl_AmendedAndRestatedCreditAgreementMember" abstract="true" name="AmendedAndRestatedCreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_PercentageOfNonDomesticCapitalStockPledgedAsCollateralForCreditFacility" abstract="false" name="PercentageOfNonDomesticCapitalStockPledgedAsCollateralForCreditFacility" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="powl_PowellUKLimitedMember" abstract="true" name="PowellUKLimitedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_CashCollateralRequiredForGuaranteesPeriod" abstract="false" name="CashCollateralRequiredForGuaranteesPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="powl_TractionPowerCustomerMember" abstract="true" name="TractionPowerCustomerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_OtherCustomersMember" abstract="true" name="OtherCustomersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_LeaseLiabilitiesAbstract" abstract="true" name="LeaseLiabilitiesAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="powl_TimeBasedRestrictedStockUnitMember" abstract="true" name="TimeBasedRestrictedStockUnitMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_AllowanceForDoubtfulAccountsReceivableWriteOffsRecoveries" abstract="false" name="AllowanceForDoubtfulAccountsReceivableWriteOffsRecoveries" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="powl_ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualSharesIssuable" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualSharesIssuable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="powl_MexicoCentralAmericaAndSouthAmericaMember" abstract="true" name="MexicoCentralAmericaAndSouthAmericaMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_NonEmployeeDirectorEquityIncentivePlanMember" abstract="true" name="NonEmployeeDirectorEquityIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_OperatingLeaseRightOfUseAssetLeaseAccrual" abstract="false" name="OperatingLeaseRightOfUseAssetLeaseAccrual" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="powl_IncreaseDecreaseDueToForeignCurrencyTranslation" abstract="false" name="IncreaseDecreaseDueToForeignCurrencyTranslation" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="powl_ShorttermInvestmentsFairValueDisclosure" abstract="false" name="ShorttermInvestmentsFairValueDisclosure" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
