GE 850 - Page 445

CHAPTER 7: MONITORING FUNCTIONS
850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL 7–25
Figure 7-16: Current Demand logic diagram
894060A2.cdr
LED: PICKUP
Current Inputs Phase A Current (IA)
SETPOINTS
BLOCK : Off=0
AND
SETPOINTS
FUNCTION : Disabled Alarm Latched Alarm Configurable
OR
SETPOINTS
MEASUREMENT TYPE : Calculate Phase A CURRENT DEMAND
SETPOINTS
PICKUP : IA Demand ≥PICKUP RUN
Current Dmd1 PKP
AND AND
Command
RESET
OR
LED: ALARM
THERMAL 90% RESPONSE TIME : TIME INTERVAL :
Phase B Current (IB)
Calculate Phase B CURRENT DEMAND
Phase C Current (IC)
Calculate Phase C CURRENT DEMAND
IB Demand ≥PICKUP RUN IC Demand ≥PICKUP RUN
OR
Current Dmd1 PKP A
Current Dmd1 PKP B Current Dmd1 PKP C
SETPOINTS
OUTPUT RELAYS
Do Not Operate , Operate
FlexLogic Operands
S
LATCH
Set-
Dominant
R
SETPOINTS
SIGNAL INPUT: CT Bank 1 - J1
USED ONLY IN 845