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Reply To: Protection Riddle No.11 – Earthing point location

#1243
kissan from Mauritania

    The relaying point being the star point of earthing transformer will be able to detect the earth fault at bus bar level, whilst the CTS on individual sources will not be able to detect the earth fault as they can see only an overcurrent. It is evident that, in case of an earth fault, the feeding sources will have to be tripped, i.e with tie breaker open condition, the feeding circuit breakers on the relecant section on which the fault occurs will have to be tripped. For tie breaker closed position the control circuit of the protection devise has to be wired , so that they can trip the related source. The above configuration is not a very common one and thus it has its inherent difficulties.