Function
Settings
Maximum/minimum
(=range)
Frequency measurement
(FMMXU)
F deadband
75/35 (=40 Hz)
1
Phase sequence current
measurement (CSMSQI)
Ps Seq A deadband
,
Ng Seq A
deadband
,
Zro A deadband
40/0 (=40xIn)
Phase sequence voltage
measurement (VSMSQI)
Ps Seq V deadband
,
Ng Seq V
deadband
,
Zro V deadband
4/0 (=4xUn)
Three-phase power and ener-
gy measurement (PEMMXU)
-
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.
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
=
⋅
+
⋅
+
⋅
(U
I
U
I
U
I
A
A
B
B
C
C
*
*
*
)
(Equation 178)
Once the complex apparent power is calculated, P, Q, S and PF are calculated with
the equations:
P
S
=
Re( )
(Equation 179)
Q
S
=
Im( )
(Equation 180)
S
S
P
Q
=
=
+
2
2
(Equation 181)
Cos
P
S
ϕ
=
(Equation 182)
Depending on the unit multiplier selected with
Power unit Mult, the calculated
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)
Measurement functions
1MRS757644 H
932
620 series
Technical Manual
