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Protection Riddle No.103 - Dead Zone
Can anyone tell what is the dead Zone?
2ndly how to calculate the I Burden of Current Transformer?
Author : Unknown
Sat, April 20th, 2013 - 12:32
In busbar protection as showing in figure below,when the fault occurrs in point A, the small differential current of bus Ⅱis 0 and the protection device judges that the fault happens outside the protection zone,then the differential protection of bus-II will not act. The differential current of bus I is not 0.So the differential protection of bus-I cuts down all connected components of bus I and the bus coupler switch.However, the fault still exists.Therefore, the fault which happens between bus coupler switch and bus coupler CT is dead-zone fault of the bus differential protection.

In line distance protection as showing in figure below, when fault occurs in illustrated point between opened circuit breaker and current transformer, the distance relay won't receive any voltage signal and could not suitable response. This short zone is named line protection dead zone.

Author : Hamid - From: Iran
Mon, April 22nd, 2013 - 13:30
Can u please tell what is the 'I' Burden and 'V' Burden of C.T ?  
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