GE Multilin 850

4–252 850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
PROTECTION CHAPTER 4: SETPOINTS
Figure 4-104: Fast Underfrequency logic diagram
SETPOINT
BLOCK : Off=0
AND
SETPOINT
FUNCTION : Alarm Latched Alarm Configurable
FlexLogic Operands
AND AN D
Command
RESET
OR
LED: ALARM
S
LATCH
Set-
Dominant
R
SETPOINT
OUTPUT RELAY 3(X): Do Not Operate , Operate
Disabled
J2 Voltage Input
Fast UF 1 PKP Fast UF 1 OP
SETPOINT
WYE DELTA
VA VAB VB VBC VC VCA
Vx
V ≥ MINIMUM RUN
SETPOINT
Positive -
sequence
Composite
FREQUENCY INPUT :
MINIMUM VOLTAGE :
SETPOINT
0 < f < PICKUP
RUN
UF PICKUP :
SETPOINT
df/dt < PICKUP RUN
ROC PICKUP :
Frequency f Rate of Change df /dt
SETPOINT
TYPE: UF Only UF and df/dt
ANDAND
OR
SETPOINT
Counter
RUN
SEMICYCLES SET :
RESET
SETPOINT
Counter
RUN
SEMICYCLES RESET :
RESET
SETPOINTS
RESET DELAY : t
PKP
t
RST
PICKUP DELAY :
LED: PICKUP
Trip
OR
AND
LED: TRIP
Trip