Cb Fail General Logic - GE MiCOM P40 Agile Technical Manual

P44x/EN AP/Hb6
(AP) 5-118
Initiation
(Menu selectable)
External protection -
The phase selection must be performed by creating dedicated PSL.
The circuit breaker failure protection incorporates two time-delays, 'CB Fail 1 Timer' and
'CB Fail 2 Timer', allowing configuration for the following scenarios:
Figure 89: CB Fail general logic
• Simple CBF, where only 'CB Fail 1 Timer' is enabled. For any protection trip, the 'CB
Fail 1 Timer' is started, and normally reset when the circuit breaker opens to isolate
the fault. If breaker opening is not detected, 'CB Fail 1 Timer' times out and closes an
output contact assigned to breaker fail (using the programmable scheme logic). This
contact is used to backtrip upstream switchgear, generally tripping all infeeds
connected to the same busbar section.
• A re-tripping scheme, plus delayed back-tripping. Here, 'CB Fail 1 Timer' is used to
route a trip to a second trip circuit of the same circuit breaker. This requires duplicated
CB fail timer reset mechanism
Three options are available. The user can select any or all of
the options.
[All I< and IN< elements operate]
[External trip reset]
AND [All I< and IN< elements operate]
CB open (all 3 poles)
AND [All I< and IN< elements operate]
Application Notes
MiCOM P40 Agile P442, P444