Current Supervision - GE 850 Instruction Manual

AUTORECLOSE

Current Supervision

NOTE:
NOTE
8–92
Path:
Setpoints > Control > Autoreclose 1 > Current Supervision
The Current Supervision feature is used to limit breaker wear. When a fault current exceeds
user-programmed levels, it reduces the number of Reclose shots permitted. Once a
Reclose sequence is initiated, the maximum current measured on any phase is compared
to the setpoint current levels. The relay then determines the maximum number of shots
allowed or whether the scheme goes immediately to Lockout. The lowest number of
permitted shots, whether set by the MAX NUMBER OF RECLOSE SHOTS setpoint or the
Current Supervision feature, always takes precedence unless Current Supervision takes the
scheme to Lockout. Lockout has the highest priority. Once the Current Supervision feature
has reduced the total number of shots, a subsequent shot can still reduce the limit further.
The fault current level above which the number of Autoreclosure shots will be reduced to
one, two, or three shots can be selected. If the Autoreclose scheme is to be taken directly
to Lockout without reclosing, set the TO LOCKOUT setpoint to "Enabled".
FUNCTION
Range: Disabled, Enabled
Default: Disabled
SIGNAL INPUT
Range: dependant upon the order code
Default: CT Bank 1-J1
This setting provides selection of three-phase current input source for current
supervision.
Since AR1 applies to BKR1, and AR2 applies to BKR2, the user must select the CT bank that
is associated with the breaker to which the autoreclosure applies.
3 SHOTS FOR CURRENT ABOVE
Range: 0.050 to 30.000 x CT in steps of 0.001 x CT
Default: 17.000 x CT
The setpoint specifies fault current level, which, when exceeded, reduces the permitted
number of Reclose shots to 3.
2 SHOTS FOR CURRENT ABOVE
Range: 0.050 to 30.000 x CT in steps of 0.001 x CT
Default: 18.000 x CT
The setpoint specifies fault current level, which, when exceeded, reduces the permitted
number of Reclose shots to 2.
1 SHOT FOR CURRENT ABOVE
Range: 0.050 to 30.000 x CT in steps of 0.001 x CT
Default: 19.000 x CT
The setpoint specifies fault current level, which, when exceeded, reduces the permitted
number of Reclose shots to 1.
LOCKOUT FOR CURRENT ABOVE
Range: 0.050 to 30.000 x CT in steps of 0.001 x CT
Default: 20.000 x CT
The setpoint specifies the fault current level, which, when exceeded, sets the Shot
Counter to maximum and with Reclosure initiates taking the scheme to Lockout without
reclosing. For this setting to take effect Current Supervision to Lockout must be enabled.
850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 8: CONTROL