GE Multilin 850

CHAPTER 4: SETPOINTS PROTECTION
850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL 4–163
Figure 4-63: Restricted Ground (Earth) Fault Protection Logic Diagram
89$1.cdr
SETPOINTS
RGF 1 FUNCTION: Alarm Latched Alarm
OR
AND
LED: ALARM /
LATCHED ALARM
Command
AND
S R
LATCH # 1
Set-
Dominant
Configurable
FlexLogic Operands
RGF 1 OP
SETPOINTS
Do Not Operate, Operate OUTPUT RELAY 3 (X)
Source IB Source IC
AND
SETPOINTS
RGF 1 BLOCK : Off = 0 Source IA Disabled
OR
RESET
Igd Imax Igd >= I pickup RUN
SETPOINTS
RGF 1 PICKUP DELAY:
t
PKP
0
Select highest value
Imax = max (Ia,Ib,Ic)
Trip
Operate Output Relay 1 (TRIP)
LED: TRIP
AND
Igd = |3Io + Ig|
Calculate 3Io
SETPOINTS
RGF 1 PICKUP: RGF 1 SLOPE:
Source Ig
> =
AND
SETPOINTS
RGF 1 GND CURR SUPERV: Disabled = 0 Enabled = 1 RGF 1 GND CURR SUPERV LEVEL : Ig > I Level
OR
AND
RGF 1 PKP
LED: PICKUP
RGF 1 Superv ON
METERING
I0 Ig Igd
Currents