CMC 356 Reference Manual806.10.6.5 Accuracy of Power MeasurementGeneralThe power is calculated from one current channel and one voltage channel:Active power: [W]Apparent power: S = Vrms x Irms [VA]Reactive power: [var]U rms = , Irms =AccuraciesConditions: integration time 1s, measurement signal sinusoidal, excitation10-100 %, accuracy references the apparent power, error of the currentclamp is not taken into account.Table 6-38:Sampling rates28.44kHz9.48kHz3.16kHzTable 6-39:Sampling rate28.44kHzP 1T---= * u t( )*i t( ) td0TQ S2 P2–= *sign_Q1T---* u t( )2 td0T 1T---* i t( )2 td0TFrequency range Power Accuracy 1AC Typical Guaranteed10 Hz ... 100 Hz S ± 0.3 % ± 0.7 %P ± 0.3 % ± 0.7 %Q ± 0.8 % ± 2 %Frequency range Power Accuracy 11S = Apparent powerP = Active powerQ = Reactive powerAC Typical Guaranteed10 Hz ... 2.2 kHz S + 0.3 % / - 1.2 % ± 2.5 %P + 0.3 % / - 1,2 % ± 2.5 %Q + 0.8 % / - 2.5 % ± 3.5 %Actual - ExpectedFull scale x 100 %Relative error:
