A new principle of fault line selection for distribution

Fault line selection is important to maintenance and normal operation of power distribution system. If a fault does not disappear for a long time, it could develop into a phase to phase fault. Then the fault line should be found out as quickly as possible and the fault should be removed. Thus, to select a good method of fault line selection is necessary. A transient signal may be a selection for fault line selection. A travelling wave is a transient signal. It will be more suitable to analyzing the single phase to ground fault because the fault itself is a transient process. But there are two problems to effect the use of the travelling wave signal: first, it is a high frequency signal, so it is hard to distinguish from noise; and secondly there is lack of a proper method to detect and describe the travelling wave signal. Traditional power signals analysis tools are limited in the presence of nonsteady signals. The travelling wave signal possesses a mutant property. In mathematics, it is the function of not only time but also frequency. These problems are solved with the wavelet transform. The new principle of fault line selection based on travelling waves and wavelet transform is presented