P74x/EN OP/N
(OP) 5-
No CB status available directly affects any function within the relay that requires this signal,
for example CB control, Topology for buscoupler, etc.
If both 52A and 52B are used then status information will be available and in addition a
discrepancy alarm will be possible, according to the following table. 52A and 52B inputs are
assigned to relay opto-isolated inputs via the PSL.
Auxiliary Contact Position CB State Detected Action
52A 52B
Open Closed Breaker Open Circuit breaker healthy
Closed Open Breaker Closed Circuit breaker healthy
Closed Closed State Unknown
Alarm raised if the condition
persists for longer th
an “CB
supervision timer” delay time
setting
Open Open State Unknown
Alarm raised if the condition
persists for longer than “CB
supervision timer” delay time
setting
In the bus sections and bus couplers, the position used in the topology algorithm is open
when the ‘CB State Detected’ is ‘Breaker Open’. In all others cases, the position closed will
be used to calculate the topology. CB auxiliary contacts and Manual CB closed command
are definitely required for all bus-sections and bus-couplers.
They are not definitely required for feeders, but if the information is supplied to the scheme,
better operation is possible:
• Dead Zone fault, the CB position is required (send remote trip order to the other end of
the line).
• CB supervision.
In that case the best is to provide the Manual CB closing order.
No specific auxiliary contacts are required but ideally one 52a and one 52b should be
available.
The faster these contacts operate (following real CB operation) the better it is.
When 52a=52b=0 or 52a=52b=1 (most of the time during operation of the CB, but not only),
the CB is considered as closed in the topology.
In the PSL:
If 52a is per pole, 52b should be per pole;
If 52a is 3phase, 52b should be 3phase too.
It is recommended to use early make late break contacts for the coupler breaker.
If they do not exist, the CB Close command shall be used to force closed the breaker during
the closing process; this choice is made in the PSL.
To Next Page
Loading...
