GE Multilin 850

4–184 850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
PROTECTION CHAPTER 4: SETPOINTS
Figure 4-72: Thermal Overload 1 Protection logic diagram
Current Inputs
Phase A Current (IA) Phase B Current (IB)
Phase C Current (IC)
SETPOINTS
BLOCK: Off=0
AND
SETPOINTS
THERMAL OVERLOAD 1 FUNCTION: Disabled Trip Alarm Latched Alarm Configurable
OR
SETPOINTS
CABLE THERMAL MDL COOL TIME CONSTANT :
THERMAL
MODEL (θ)
FlexLogic Operands
AND AND AND
Command
RESET
OR
LED: ALARM
LED: TRIP
Operate Output Relay 1 (TRIP)
RUN
SETPOINTS
OUTPUT RELAYS (3-7):
Do Not Operate, Operate
CABLE THERMAL MDL HEAT TIME CONSTANT : THERMAL OVERLOAD 1 PICKUP:
θ
A
≥ 1
θ
C
≥ 1
θ
B
≥ 1
SETPOINTS
THERMAL OVERLOAD 1 ALARM: θ
A
> ALARM
θ
C
> ALARM
θ
B
> ALARM
OR
Thermal 1 OP A
Thermal 1 OP B Thermal 1 OP C
Thermal 1 Alarm A
Thermal 1 Alarm B Thermal 1 Alarm C
Thermal 1 Alarm
OR
Thermal OP
SETPOINTS
THERMAL OVERLOAD 1 PICKUP: I
A
> PICKUP
I
C
> PICKUP
I
B
> PICKUP
OR
Thermal 1 PKP A
Thermal 1 PKP B Thermal 1 PKP C
Thermal 1 PKP
LED: PICKUP
RUN
S
LATCH
Set-
Dominant
R
SETPOINTS
SIGNAL INPUT: CT Bank 1 - J1
850 Only
894045A3.cdr