GE 845 Instruction Manual page 358

PROTECTION
FASTPATH:
4–230
PICKUP
Range: 20.00 to 65.00 Hz in steps of 0.01 Hz
Default: 59 Hz
PICKUP DELAY
Range: 0.000 to 6000.000 s in steps of 0.001 s
Default: 2.000 s
DROPOUT DELAY
Range: 0.000 to 6000.000 s in steps of 0.001 s
Default: 2.000 s
MINIMUM VOLTAGE
Range: 0.000 to 1.250 x VT in steps of 0.001 x VT
Default: 0.700 x VT
The setting sets the minimum voltage for Underfrequency element operation specified
per times VT. The setpoint prevents incorrect operation before energization of the source
to the relay location, and during voltage dips.
If the 3-phase VT uses a delta connection and SIGNAL INPUT is set to Ph VT Bnk1-J2, the
positive sequence voltage is used as the supervision voltage. In such condition, the true
supervision level is internally changed to 1/sqrt(3) of the user setting since the base of VT
here is the phase-phase voltage.
MINIMUM CURRENT
Range: 0.000 to 30.000 x CT in steps of 0.001 x CT
Default: 0.200 x CT
The setting sets the minimum value of current required on any phase to allow the
Underfrequency element to operate. The setpoint is used to prevent underfrequency
tripping during periods of light load, when this action would have an insignificant effect
on the system. A setting of zero is suspend current supervision.
BLOCK
Range: Off, Any FlexLogic operand
Default: Off
OUTPUT RELAY X
For details see Common
EVENTS
Range: Enabled, Disabled
Default: Enabled
TARGETS
Range: Disabled, Self-reset, Latched
Default: Self-reset
Setpoints.
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS