三相四线电能表有功功率表达式():
AP=UAIAcosφA+UBIBcosφB+UCICcosφC
BP=UAIAsinφA+UBIBsinφB+UCICsinφC
CP=UAIAtgφA+UBIBtgφB+UCICtgφC
DP=UAIActgφA+UBIBctgφB+UCICctgφC
AP=UAIAcosφA+UBIBcosφB+UCICcosφC
BP=UAIAsinφA+UBIBsinφB+UCICsinφC
CP=UAIAtgφA+UBIBtgφB+UCICtgφC
DP=UAIActgφA+UBIBctgφB+UCICctgφC