GE Multilin 850

CHAPTER 4: SETPOINTS MONITORING
850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL 4–291
Figure 4-126: Harmonic Detection logic diagram
894000A2.cdr
LED: PICKUP
SETPOINT
BLOCK : Off=0
AND
SETPOINT
FUNCTION : Disabled Alarm Latched Alarm Configurable
OR
SETPOINT
PICKUP : W1_HDF ≤ PICKUP RUN
SETPOINT
PICKUP DELAY : t
PKP
0
W1 Harm Derat OP
FlexLogic Operands
W1 Harm Derat PKP
AND AN D
Command
RESET
OR
LED: ALARM
SETPOINT
MINIMUM OPER CURRENT : IA ≥ MINIMUM RUN
S
LATCH
Set-
Dominant
R
Phase A Current (IA) Phase B Current (IB)
Phase C Current (IC)
Phase A Harmonics Phase B Harmonics
Phase C Harmonics
IB ≥ MINIMUM IC ≥ MINIMUM
SETPOINT
OUTPUT RELAY X Do Not Operate , Operate
W1 Current Harmonics
W1 Current Input
Calculate Harmonic
Derating Factor
(W1_HDF)
AND
Phase A Harmonics Phase B Harmonics
Phase C Harmonics
W2 Current Harmonics
Calculate Harmonic
Derating Factor
(W2_HDF)
Phase A Harmonics Phase B Harmonics
Phase C Harmonics
W3 Current Harmonics
Calculate Harmonic
Derating Factor
(W3_HDF)
Load Limit Reduced
LED: LOAD-LIMIT
REDUCED
W2_HDF < 0.96 W1_HDF < 0.96 W3_HDF < 0.96
OR