GE 850 - Page 340

6–72 850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
CURRENT ELEMENTS CHAPTER 6: PROTECTION SETPOINTS
Figure 6-28: Broken Conductor Protection logic diagram
LED: PICKUP
Current Inputs
Negative Current (I2)
Positive Current (I1)
SETPOINTS
BLOCK: Off=0
AND
SETPOINTS
BROKEN CONDUCTOR FUNCTION: Disabled Trip Alarm Latched Alarm Configurable
OR
AND
SETPOINTS
BROKEN CONDUCTOR I_1 MIN:
|I_1| > I_1 MIN
RUN
SETPOINTS
BROKEN CONDUCTOR PICKUP DELAY:
2 cyc 0
Broken Cond OP
FlexLogic Operands
Broken Cond PKP
AND AND AND
Command
RESET
S
LATCH
Set-
Dominant
R
OR
LED: ALARM
LED: TRIP
Operate Output Relay 1 (TRIP)
Phase A Current (IA) Phase B Current (IB)
Phase C Current (IC)
|IA| < I_1 MIN |IC| < I_1 MIN |IB| < I_1 MIN |IA’| - |IA| > 0.05pu |IC’| - |IC| > 0.05pu |IB’| - |IB| > 0.05pu
I’ is 4 cycles old
SETPOINTS
BROKEN CONDUCTOR I_1 MAX: |I_1| < I_1 MAX BROKEN CONDUCTOR I_2/I_1 RATIO: |I_2|/|I_1| > RATIO BROKEN CONDUCTOR I_1 MIN:
AND AND
RUN
OR
OR
AND
t
PKP
0
SETPOINTS
OUTPUT RELAYS (3-7):
Do Not Operate, Operate
SETPOINTS
SIGNAL INPUT: CT Bank 1 - J1
894043A2.cdr