A single-ended traveling wave based fault location method using DWT in hybrid parallel HVAC/HVDC overhead transmission lines on the same tower

In this paper, a single ended traveling wave based fault location method is presented for Hybrid Parallel HVAC/ HVDC Overhead Transmission Lines (HPOTLs) on the same tower using Discrete Wavelet Transform (DWT). In HPOTLs, the AC and DC transmission lines are adjacent to each other from the sending to the receiving end of the lines and there is electromagnetic coupling between them. Fault detection and classification algorithms in HPOTLs are presented in another paper. Therefore, in order to summarizing, in this paper, it is assumed that the fault is detected in the HVAC or/and HVDC lines and faulty line is identified. HPOTL faults include AC faults, DC faults and AC/DC intersystem faults. AC and DC voltage signals on sending end of the transmission line with a sampling frequency of 100 kHz are used for fault location in this paper. In order to minimize the noise effect, the squared wavelet transform coefficients (WTC2) is used for proposed fault location method. Finally, BewleyLattice diagrams are checked for the traveling wave pattern and locate the fault. At the end of paper, it has been shown that the proposed method has high accuracy, noise immunity, robustness against fault inception angles, and high impedance faults.