ABB Relion REC670 Applications Manual page 174

Section 7
Current protection
1000 200[
=
I
r
IEC09000755 V1 EN-US
or on the secondary CT side:
=
I
r S _ ec
IEC09000756 V1 EN-US
Note that the SCB rated current on the secondary CT side is important for secondary injection
of the function.
The parameters for the Capacitor bank protection function CBPGAPC are set via the local HMI
or PCM600. The following settings are done for this function:
General Settings:
Operation = On ; to enable the function
IBase = 289A ; Fundamental frequency SCB rated current in primary amperes. This value is used
as a base value for pickup settings of all other features integrated in this function.
Reconnection inhibit feature:
OperationRecIn = On ; to enable this feature
IRecnInhibit< = 10% (of IBase ); Current level under which function will detect that SCB is
disconnected from the power system
tReconnInhibit = 300s ; Time period under which SCB shall discharge remaining residual voltage
to less than 5%.
Overcurrent feature:
OperationOC = On ; to enable this feature
IOC> = 135% (of IBase ); Current level for overcurrent pickup. Selected value gives pickup
recommended by international standards.
tOC = 30s ; Time delay for overcurrent trip
Undercurrent feature:
OperationUC = On ; to enable this feature
IUC< = 70% (of IBase ); Current level for undercurrent pickup
tUC = 5s ; Time delay for undercurrent trip
Reactive power overload feature:
OperationQOL = On ; to enable this feature
168
×
MVAr ]
=
289
×
3 400[ kV ]
289 A
=
0.578 A
500 1
Undercurrent feature is blocked by operation of Reconnection inhibit feature.
A
1MRK 511 358-UEN A
(Equation 89)
(Equation 90)
Application manual