Pole Dead Function; Pole Dead Logic; Figure 134: Pole Dead Logic - GE P4A Technical Manual

Chapter 12 - Monitoring and Control
8

POLE DEAD FUNCTION

The Pole Dead Logic is used to determine and indicate that one or more phases of the line are not energised. A
Pole Dead condition is determined either by measuring:
the line currents and/or voltages, or
●
by monitoring the status of the circuit breaker auxiliary contacts, as shown by dedicated DDB signals.
●
It can also be used to block operation of underfrequency and undervoltage elements where applicable.
8.1

POLE DEAD LOGIC

IA
I< Current Set
VA
V <
CB Open A ph
IB
I< Current Set
VB
V <
CB Open B ph
IC
I< Current Set
VC
V <
VTS Slow Block
CB Open C ph
CB Open 3 ph
V 01247

Figure 134: Pole Dead logic

If both the line current and voltage values fall below a certain threshold, or a CB Open condition is asserted from
the state control logic, the device initiates a Pole Dead condition. The current and voltage thresholds can be set
with the I< Current Set and the V< settings respectively, in the CBFAIL&P.DEAD column.
If one or more poles are dead, the device indicates which phase is dead and asserts the Any Pole Dead DDB
signal. If all phases are dead the Any Pole Dead signal is accompanied by the All Poles Dead signal.
If the VT fails, a VTS Slow Block signal is taken from the VTS logic to block the Pole Dead indications that would be
generated by the undervoltage and undercurrent thresholds.
266
20 ms
&
1
20 ms
&
1
20 ms
&
1
P54A/B/C/E
Pole Dead A
Pole Dead B
Pole Dead C
1 Any Pole Dead
& All Poles Dead
P54xMED-TM-EN-1