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Reply To: Protection Riddle No.38 – Restricted earth fault protection and Inrush current

#1595
Hamid

    Please note, high impedance type restricted earth fault relays just contain one signal input and individual phase current do not insert to relay. In low impedance type equally, the function of relay is related to zero sequence calculator stage of relay; therefore the phase unbalance of inrush current cannot cause relay mal-operation. So REF must be stable against through zero sequence inrush current theoretically.