ABB Relion 670 Series Technical Reference Manual page 842

Section 13
Scheme communication
836
in any phase, COUVGAPC (59_27) generates pickup and trip signals for that phase
and common pickup and trip signals. Independent enabling for overvoltage and
undervoltage are available with definite time delay. If shunt reactor is not present in the
system, COUVGAPC (59_27) does not include any effect of shunt reactor while
calculating the compensated voltage. This shunt reactor calculation is enabled when
both input SWIPOS is and setting parameter EnShuntReactor is Enabled. Run time
change in EnShuntReactor setting parameter restarts the IED and SWIPOS input signal
is used to enable/disable the shunt reactor calculations.
Calculations
• All resistance and reactance considered in compensated voltage calculation are
primary side values.
• Calculation of shunt reactor reactance in ohms from given MVAr rating:
2
V
=
X N
sr
Q
N
EQUATION2249-ANSI V1 EN
Where:
V
line to line voltage
N
Q is total three phase MVAr of shunt reactor
N
• If total line capacitance (C
2
=
X
w
cp
C
total
EQUATION2250 V1 EN
and if total line capacitive reactance X
=
2 X
X
cp cTotal
EQUATION2251 V1 EN
Compensated voltage for all three phases is available as service values.
) is known then half line capacitive reactance:
total
is known:
cTotal
1MRK505222-UUS C
(Equation 155)
(Equation 156)
(Equation 157)
Technical reference manual