A New Digital Feed Circuit Protection Using Directional Element

The paper presents the application of a new directional relaying principle to a tapped feeder. The possibility of failure to trip for a fault on the protected line must be taken into account when supply to at least one of the line terminals is cut off or when the keying element sensitivity is insufficient. This has been achieved by using the pre-fault voltage and fault current signals. The pre-fault voltage signal is compensated to be synchronized with the fault current signal. Two directional quantities are derived at the buses that have two circuits. A fault characteristic is suggested to easily identify the forward and reverse faults.