GE 869 - Page 393

CHAPTER 4: SETPOINTS PROTECTION
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL 4–261
Figure 4-101: Frequency Rate-of-Change Protection logic diagram
LED: PICKUP
Current Inputs
Phase A Current (IA) Phase B Current (IB) Phase C Current (IC)
SETPOINTS
BLOCK : Off=0
AND
SETPOINTS
FREQ RATE FUNCTION : Disabled Trip Alarm Latched Alarm Configurable
OR
Positive -
sequence
SETPOINTS
FREQ RATE MINIMUM CURRENT : I = MINIMUM
SETPOINTS
FREQ RATE MINIMUM VOLTAGE :
AND
SETPOINTS
FREQ RATE PICKUP : -df/dt = PICKUP
FREQUENCY f
RUN
SETPOINTS
FREQ RATE PICKUP DELAY : t
PKP
0
FreqRate1
OP
FlexLogic Operands
FreqRate1 Up PKP
AN D AND AND
Command
RESET
OR
LED: ALARM
LED: TRIP
Operate Output Relay 1 (TRIP)
RATE OF CHANGE df /dt
SETPOINTS
FREQ RATE TREND : Decreasing Increasing Bi-directional
SETPOINTS
FREQ RATE MIN FREQUENCY : FREQ RATE MAX FREQUENCY :
AND
AND
SETPOINTS
FREQ RATE PICKUP : df/dt = PICKUP
RUN
SETPOINTS
FREQ RATE PICKUP DELAY : t
PKP
0
OR
FreqRate1
Dwn OP
FreqRate1 Up OP
FreqRate1
PKP
FreqRate1
Dwn PKP
OR
RUN
V = MINIMUM RUN
f > MIN & f < MAX
RUN
SETPOINTS
OUTPUT RELAY 3 (X) Do Not Operate , Operate
S
LATCH
Set-
Dominant
R
OR OR
None
WYE DELTA
VA VAB VB
VBC
VC
VCA
Vx
SETPOINTS
FREQ RATE FREQUENCY INPUT :
Positive -
sequence
Composite
Voltage Inputs
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