A Self-healing Scheme of Single-phase-to-ground Fault in Smart Power Distribution System

The paper presents a self-healing scheme of single-phase-to-ground fault in smart power distribution system. The scheme consists of three parts: single-phase-to-ground fault detection, faulted feeder selection and faulted feeder isolation. Fault detection is based on power-frequency voltage measured by a voltage transducer. A single-phase-to-ground fault is detected when measured voltage is greater than threshold. A fault generated current traveling waves are used to identify faulted feeder. The feeder with different initial traveling wave's polarity to other feeders is selected as faulted feeder. When faulted feeder is identified, the interconnection switch between different bus-bar is switched on firstly, then the switch at the load side of faulted feeder is switched off to isolate the load from the fault, the switch at the power source side of faulted feeder is switched off to isolate the source from the fault lastly. Simulation studies show that the scheme can meet the requirements of isolating single-phase-to-ground fault without affecting power supply to the load.