This paper introduces a single-terminal travelling wave fault location system based on high speed data acquisition system. It lowers the error originated from the acquisition system to 3 m. Singularity point is identified by wavelet transformation on the travelling wave coming from the fault position. The interferences coming from the adjacent and the opposite buses can be eliminated by waveform comparison method. As a result

the time difference of travelling wave propagation can be evaluated accurately

hence realizing the fault location of EHV transmission line.