Fault Distance Measurement Based on Active Waveform Disturbance

Single-phase grounding faults are the most common type of faults in power distribution systems. Due to the large number of branches and the coexistence of overhead lines and cable lines, the single-phase grounding faults is difficult to locate accurately. In response to this problem, a single-phase grounding fault distance measurement technology for distribution lines based on active disturbance is proposed. When a single-phase grounding fault occurs in the distribution line, the power electronic switch used to switch the damping resistance of the arc suppression coil is switched off for a short time, so that the transient disturbance waveforms of the voltage and current with controllable intensity and characteristics can be produced. At the waveform measurement point of the feeder, based on the multi-frequency components in the effective frequency band of the disturbance voltage and current, the fault distance measurement equations are established. Then by using the hypothesis testing method and comparing the residuals of the fault distance measurement equations, the fault section is determined and the fault distance are provided. Due to the rich frequency components contained in the disturbance, the method can be applied to the fault location of the radial distribution network composed of mixed lines. It also can eliminate the falsity of the fault points and reduce the error caused by the changes of line parameters.