Effective fault location technique in three-terminal transmission line using Hilbert and discrete wavelet transform

In this paper, an effective fault location technique based on transient voltage signals for three terminal lines using digital signal processing (DSP) method is proposed. In the proposed method, to locate the faults, Hilbert transform (HT) and discrete wavelet transform (DWT) have been used. These methods have been applied to the modal components of synchronized voltage signals. Then, by extracting the arrival time of first wave head at all terminals and a comparison between these arrival times, the algorithm of fault section identification and fault location calculation are presented. The simulated signals corresponding to different fault conditions are obtained from PSCAD/EMTDC environment and using frequency-dependent transmission line. MATLAB software is used to analyze the voltage signals and to calculate the fault location. Numerical results shows the accurate performance of the proposed methods under different fault conditions for three-terminal transmission lines.