ABB RELION SMU615 Technical Manual page 188

Measurement functions
Function
Frequency measurement (FMMXU)
Phase sequence current measurement
(CSMSQI)
Phase sequence voltage measure-
ment (VSMSQI)
Three-phase power and energy meas-
urement (PEMMXU)
Power and energy calculation
The three-phase power is calculated from the phase-to-earth voltages and phase-
to-earth currents. The power measurement function is capable of calculating a
complex power based on the fundamental frequency component phasors (DFT).
S =
Once the complex apparent power is calculated, P, Q, S and PF are calculated with
the equations:
P = Re( )
Q = Im( )
S
=
Cos
Depending on the unit multiplier selected with
power values are presented in units of kVA/kW/kVAr or in units of MVA/MW/MVAr.
1
The value provided is for 50 Hz network. The value for 60 Hz network is 90/36 (=54 Hz)
188
In the three-phase power and energy measurement function PEMMXU,
the deadband supervision is done separately for apparent power S, with
the preset value of fixed 10 percent of the Sn, and the power factor PF,
with the preset values fixed at 0.10.. All the power measurement-related
values P, Q, S and PF are reported simultaneously when either one of the
S or PF values exceeds the preset limit.
* *
(U I U I U
⋅ + ⋅ +
A B
A B C
S
S
2 2
S P Q
= +
P
ϕ =
S
Settings
F deadband
Ps Seq A deadband, Ng Seq A
deadband, Zro A deadband
Ps Seq V deadband, Ng Seq V
deadband, Zro V deadband
-
*
I )
⋅
C
Power unit Mult , the calculated
1MRS758407 C
Maximum/
minimum
(=range)
75/35 (=40 Hz) 1
40/0 (=40xIn)
4/0 (=4xUn)
(Equation 10)
(Equation 11)
(Equation 12)
(Equation 13)
(Equation 14)
SMU615
Technical Manual