Study on faulty feeder selection methods of single-phase earthed fault in non-solidly grounded systems

When a single-phase earthed fault happened in non-solidly grounded systems, it is very important to select the faulty feeder rapidly in order to improve the power supply reliability. All currently used detection principles of single-phase earthed fault are analyzed in the paper. The advantages and disadvantages of each selection principle are also summarized. Finally, it presents my view on single-phase earthed fault detection: detection methods using transient signals have better sensitivity than that using steady state signals; it is not only applicable for Peterson coiled systems, but also applicable for intermittent arc earthed fault. With the development of modern microelectronic technique, the transient signal generated by earthed fault can be easily recorded and processed by complicated digital algorithm; hence, transient detection method must be more applicable in the future faulty feeder selection devices.