An Additional Criterion for Faulty Feeder Selection During Ground Faults in Compensated Distribution Networks

Identification of faulty feeders and sections during ground faults in compensated medium voltage systems is a complex task demanding development of new methods. Existing steady-state approaches, such as the watt-metric or the admittance based, can be compromised by various parameters of distribution lines or network configuration. Moreover, sensitivity might be threatened during high impedance faults. Transient methods (extensively studied in the recent literature) require thorough analysis before implementation due to their dependency on fault and system parameters. The current paper proposes a new approach for faulty feeder selection during ground faults. It has been tested in the laboratory utilizing electromagnetic transients program (EMTP) simulations. Performance of the developed algorithm has been compared with the conventional steady-state method implemented in a modern feeder relay. The results show improved selectivity and robustness of the new proposed algorithm. Moreover, its applicability for real systems has been demonstrated on fault records obtained from an actual distribution network. The proposed approach can be used as an additional criterion to increase selectivity of the ground fault protection in compensated networks.