Travelling wave fault location approach for MMC-HVDC transmission line based on frequency modification algorithm

Travelling wave (TW) fault location principle is widely utilized on actual power transmission line, which shows better fault location performance than conventional algorithms. But, considering the TW fault location principle is generally implemented using TW front arrival times and transmission velocities, the fault location accuracy is high influenced by frequency distortion. Meanwhile, modular multilevel converter (MMC) based high-voltage direct-current (HVDC) transmission line has more complex boundary characteristic required to be researched. Therefore, in order to acquire better fault location performance, a novel TW fault location approach for MMC-HVDC transmission line is proposed based on frequency modification algorithm. Firstly, the frequency modification algorithm of TW front is studied. Secondly, the detailed calculation principle of system impedance and transmission line's wave impedance is proposed. Thirdly, the novel TW fault location principle based on modified frequency spectrum is described. Eventually, via PSCAD/EMTDC simulation software, a typical & PLUSMN;400 kV simulation system is constructed to validate the performance of proposed TW fault location principle under the influences of fault type, fault location and grounding resistor issues.