Alstom MiCOM P846, Technical Manual

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P846/EN OP/D Operation
(OP) 5-16
MiCOM P846
I N TSIG P h a se A Undercurrent Oper a tion
2 0ms
OP
DDB CB Open C ph (777)
DDB CB Open B ph (776)
t
0
&
1
I N TSIG P h a se A Undervolt a ge Oper a tion
DDB CB Open A ph (775)
t
0
2 0ms
&
1
t
0
2 0ms
&
1
I N TSIG P h a se B Undercurrent Oper a tion
I N TSIG P h a se C Undercurrent Oper a tion
DDB CB Open 3 ph (774)
&
1
DDB P ole De a d C (357)
DDB Any P ole De a d (358)
DDB All P oles De a d (35 9 )
DDB P ole De a d B (356)
DDB P ole De a d A (355)
I N TSIG VTS Slow Block
I N TSIG P h a se B Undervolt a ge Oper a tion
I N TSIG P h a se C Undervolt a ge Oper a tion
P1112ENe
Figure 11: Pole dead logic
2.6 Circuit br onitoring
The relay incorporates circuit breaker state monitoring, giving an indication of the position of
2.6.1
e set to monitor normally open (52a) and normally closed (52b) auxiliary
aker. Under healthy conditions, these contacts will be in opposite
eaker state m
the circuit breaker, or, if the state is unknown, an alarm is raised.
Circuit breaker state monitoring features
MiCOM relays can b
contacts of the circuit bre
states. Should both sets of contacts be open, this would indicate one of the following
conditions:
−
Auxiliary contacts / wiring defective
−
Circuit Breaker (CB) is defective
−
CB is in isolated position