Figure 3.7-6 Adjacent Breaker Dead Zone trip (Dead Zone trip) Logic
For some wiring arrangement (for example, circuit breaker is located between CT and the line), if
fault occurs between CT and circuit breaker, line protection can operate to trip circuit breaker
quickly, but the fault have not been cleared since local circuit breaker is tripped. Here dead zone
protection is needed in order to trip relevant circuit breaker.
The criterion for dead zone protection is: When the 50BF_ExtStr=1 or the fault current is not clear
(50BF_NoCur=0), the dead zone startup (50BF_ExtStr2=1).
When 50BF_Enable=1 and 50BF_DeadEna=1, if the 50BF_ExtStr2=1 and CB is Open
(50BF_CB_Open=1), also any phase of current is larger than dead zone current setting. All
conditions are met and last for time delay 50BF_DeaOp_T, the 50BF_DZTrOp signal will be sent.
A typical setting of 50BF_DeaOp_T is 90...150 ms.
3.7.2.7 Breaker Failure Alarm Logic
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