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  <xs:element id="powl_NonEmployeeDirectorEquityIncentivePlanMember" abstract="true" name="NonEmployeeDirectorEquityIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="powl_DebtCovenantAllowableDeductionConsolidatedFundedIndebtednessCashPercentage" abstract="false" name="DebtCovenantAllowableDeductionConsolidatedFundedIndebtednessCashPercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="powl_PetrochemicalMember" abstract="true" name="PetrochemicalMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="powl_LossContingencyProbableLossInPeriod" abstract="false" name="LossContingencyProbableLossInPeriod" nillable="true" xbrli:periodType="duration" 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-types1:domainItemType"/>
  <xs:element id="powl_ShorttermInvestmentsFairValueDisclosure" abstract="false" name="ShorttermInvestmentsFairValueDisclosure" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" 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_DebtCovenantComponentOfCalculationOfConsolidatedFundedIndebtednessCashDeductibleAmount" abstract="false" name="DebtCovenantComponentOfCalculationOfConsolidatedFundedIndebtednessCashDeductibleAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="powl_CommercialAndOtherIndustrialMember" abstract="true" name="CommercialAndOtherIndustrialMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="powl_NumberOfProjectsCancelled" abstract="false" name="NumberOfProjectsCancelled" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="powl_NumberOfFacilities" abstract="false" name="NumberOfFacilities" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="powl_LeaseLiabilitiesAbstract" abstract="true" name="LeaseLiabilitiesAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="powl_CreditAgreementThirdAmendmentMember" abstract="true" name="CreditAgreementThirdAmendmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_LightRailTractionPowerCustomerMember" abstract="true" name="LightRailTractionPowerCustomerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_StandardAssuranceWarrantyPeriod" abstract="false" name="StandardAssuranceWarrantyPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="powl_BankOfAmericaMember" abstract="true" name="BankOfAmericaMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <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_CreditAgreementSecondAmendmentMember" abstract="true" name="CreditAgreementSecondAmendmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_CommitmentsAndContingenciesAdditionalBondingCapacity" abstract="false" name="CommitmentsAndContingenciesAdditionalBondingCapacity" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="powl_PowellUKLimitedMember" abstract="true" name="PowellUKLimitedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="powl_LeaseAssetsAbstractAbstract" abstract="true" name="LeaseAssetsAbstractAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="powl_ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualSharesIssuableGrantDateValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualSharesIssuableGrantDateValue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="powl_TimeBasedRestrictedStockUnitMember" abstract="true" name="TimeBasedRestrictedStockUnitMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1: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_FacilityAgreementMember" abstract="true" name="FacilityAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="powl_MiddleEastAndAfricaMember" abstract="true" name="MiddleEastAndAfricaMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <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_CashCollateralRequiredForGuaranteesPeriod" abstract="false" name="CashCollateralRequiredForGuaranteesPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="powl_TexasCapitalBankMember" abstract="true" name="TexasCapitalBankMember" 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-types1:domainItemType"/>
  <xs:element id="powl_IrrevocableRabbiTrustMember" abstract="true" name="IrrevocableRabbiTrustMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="powl_LesseeAssetsAndLiabilitiesTableTextBlock" abstract="false" name="LesseeAssetsAndLiabilitiesTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="powl_MexicoCentralAmericaAndSouthAmericaMember" abstract="true" name="MexicoCentralAmericaAndSouthAmericaMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="powl_AmendedAndRestatedCreditAgreementMember" abstract="true" name="AmendedAndRestatedCreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
</xs:schema>
