GE 889 - Page 395

CHAPTER 4: SETPOINTS PROTECTION
889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL 4–265
Figure 4-105: Overfrequency Protection logic diagram
LED: PICKUP
SETPOINTS
BLOCK : Off=0
AND
SETPOINTS
OVERFREQ 1 FUNCTION : Disabled Alarm Latched Alarm Configurable
OR
Voltage Inputs
None
SETPOINTS
OVERFREQ 1 PICKUP : f ≥ PICKUP RUN
SETPOINTS
OVERFREQ 1 PICKUP DELAY : t
PKP
t
DPO
OVERFREQ 1 DROPOUT DELAY :
Overfreq1 OP
FlexLogic Operands
Overfreq1 PKP
AND AND
Command
RESET
OR
LED: ALARM
SETPOINTS
OVERFREQ 1 MINIMUM OPERATING VOLTAGE : V ≥ MINIMUM FREQUENCY f RUN
SETPOINTS
RELAYS Do Not Operate , Operate
S
LATCH
Set-
Dominant
R
Trip
AN D
LED: TRIP
Operate Output Relay 1 (TRIP)
WYE
DELTA
VA
VAB
VB VBC VC VCA
Vx
SETPOINTS
OVERFREQ 1 SIGNAL INPUT
:
Positive -
sequence
Composite
894055A2.cdr