GE MI-869 - Page 465

CHAPTER 4: SETPOINTS CONTROL
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL 4–347
Figure 4-142: VT Fuse Failure logic diagram
COMPARATORS
V_2
SETPOINT
FUNCTION : Disabled Alarm
OR
OR
AND
Latched Alarm
V_2 > 0.10 p.u.
RUN
LED: ALARM /
LATCHED ALARM
RESET
Command
AND
S R
LATCH # 1
Set -
Dominant
Configurable
FlexLogic Operands
VT Fuse Fail 1 OP VT Fuse 1 V Loss
TIMER
2 cyc
20 cyc
SETPOINTS
Do Not Operate, Operate RELAYS
V_1 < 0.05 p.u.
RUN
I_1 > 0.075 p.u.
RUN
V_1 < 0.80 p.u.
RUN
I_1 < 0.05 p.u.
RUN
V_1 I_1
AND
OR
AND
AND
OR
S R S R
LATCH # 2
Reset -
Dominant
LATCH # 3
Reset-
Dominant
AND AND AND
OR
|I_1| – |I_1'| > 0.04 p.u. |I_2| – |I_2'| > 0.04 p.u. |I_0| – |I_0'| > 0.04 p.u.
Where I' is 2 cycles old
I_2 I_0
OR
RUN RUN RUN
ANDANDAND
OR
FUSE
FAILURE
FAULT
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