New algorithm for determination of faulty feeder in distribution network

This paper presents a novel approach designed for centralize substation level protection to determine the faulty feeder in a distribution network In opposite to phase-to-earth faults in the transmission networks (HV), which neutral points are solidly earthed, fault-loops in a fault-to-earth case in MV distribution networks have big impedance. Additionally during the earth-fault the transient component which provides very fast information about the disturbance in the system appears. Such signals consist of different frequency components, which result from charging or discharging of the network capacitances. From all of this reasons, detection of earth-fault and determination of a faulty feeder at a bus-bar with many outgoing feeders arises serious problems. In this paper a new approach which utilized a polarity changes between fundamental frequency component of zero sequence current and a voltage directly after the fault inception is presented. The described algorithm is designed for centralize substation level protection and therefore utilized the zero sequence bus-bar voltage and residual currents from all feeders. Provided simulation experiments in ATP/EMTP software package confirms the effectiveness of the proposed technique for selection a faulty feeder during phase-to-earth fault in different networks (directly or solidly earthed; network earthed through impedance; isolated network), and under different fault scenarios — different fault inception angles, including random mechanism and higher fault resistances.