Research on Single-terminal Fault Location Method Based on CWT Cumulative Coefficient of Traveling Wave for GIL

Abstract

In case of insulation breakdown accident of Gas insulated metal-enclosed transmission line (GIL), accurate location of breakdown position is contribute to emergency repair and rapid recovery of power transmission. This paper proposed a single-terminal fault location method based on transient voltage travelling wave. Firstly, the principle of single-terminal fault location is analyzed in GIL. The accuracy of feature time extraction of transient voltage traveling wave directly affects the error of single terminal location. In order to realize the automatic extraction of feature time of the transient voltage traveling wave and improve the accuracy of fault location in GIL, this paper proposes an extraction method of traveling wave feature time based on the cumulative coefficient of continuous wavelet transform (CWT). The single-terminal fault location method is applied in a GIL utility tunnel project. During the operation, when the GIL flashover occurred, the transient voltage generated during the breakdown was completely recorded. According to the extraction method of traveling wave feature time, the fault location is confirmed quickly. The positioning error of the method is less than 5 meters. It can be seen that the singleterminal fault location method based on CWT cumulative coefficient of traveling wave can realize the rapid and accurate location of insulation breakdown fault in GIL, which is conducive to improving the operation reliability of the power transmission system.