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Why the block "Three-Phase Series RLC Load" creates the current values twice as much on each phase?

조회 수: 2 (최근 30일)
Frequency: 50Hz. Nominal phase-to-phase voltage of Source: Unom(ph-ph)=400(V). Nominal phase voltage of Source: Unom(ph)=400/(3^0.5)=230.940(V). Nominal phase-to-phase voltage of Load in Volts RMS: 400/(2^0.5)=282.843(Vrms). Active power of Load: P=576e3(W). Inductive reactive power of Load: QL=300e3(var). Capacitive reactive power of Load: Qc=21.03e3(var). By calculation through known equation we get apparent power:S=[P^2+(QL-Qc)^2]^0.5=640e3(VA).Then we can get the current value per phase: I=S/[Unom(ph-ph)*3^0.5]=924(A). In Amperes RMS: Irms=I/(2^0.5)=653(Arms). In according with measuring current value in Amperes RMS obtaining from amperemeter (current measurement) and shown at displays, we get twice as much phase current: 1306(Arms). Although on calculation conducted phase current must be 653(Arms).

답변 (1개)

Joel Van Sickel
Joel Van Sickel 2020년 9월 2일
Hello Murat,
for your model, you are simulating with a 400V peak to peak line voltage. However, your calculations are for a 400V RMS line voltage.
Regards,
Joel
  댓글 수: 1
Murat Zhanaidarov
Murat Zhanaidarov 2020년 9월 5일
Thank you for your answer.
But I think this is not because of my calculations. My calculations only duplicate the working process of the measuring units.
When I had changed the value of Nominal phase-to-phase voltage Vn at the block "Three-Phase Series RLC Load" from 282.843 Vrms to 400 V, I got the correct value of 653 Arms.
Thus, in my opinion, may be in the block "Three-Phase Series RLC Load" are shown a wrong unit of measure for Vn parameter.

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