Study Of Fault Line Selection And Fault Location For Single-Phase Earth Fault In Non-Solid Earthed Power System Based On Wavelet Transform

This paper presents a method of fault line selection and fault location for single-phase earth fault in non-solid earthed power system based on wavelet transform. It analyses the transient course and characteristics of zero sequence current when a single-phase earth fault happened in non-solid earthed power system. A method of fault line selection which uses wavelet transform extract the transient fault information is brought forward. Transforming the post-fault transient component with wavelet, the fault line is found through comparing the magnitude and polarity of wavelet transform of zero sequence currents. This method overcomes the defects of traditional fault line selection means, which will misjudge the fault line when the steady zero sequence current is very small. It is free from the fault resistance and the neutral grounding modes and can find the fault line reliability.The research of fault location in non-solid earthed power system is relatively small in modern power system. The leading causes are the network structure of distribution system is complicated and the fault characteristics are not very obvious, which bring some problems to the research of fault location. The traveling wave fault location has high reliability, accuracy and anti-disturbance capability, and it also immunes from the...