A novel method to identify the travelling wave reflected from the fault point or the remote-end bus

Identification of the travelling wave reflected from the fault point or the remote-end bus is the core of travelling wave based single-end fault location method. Because the polarity of the travelling wave reflected from the fault point or the remote-end bus is affected by the bus configuration at both ends of the fault line, it is difficult to identify whether the travelling wave is reflected from the fault point or the remote-end bus using the polarity of single modal travelling wave barely. This paper proposes a new identification method based on the cross transmission phenomenon of modal travelling waves under the scenario of single-phase-to-ground fault. Firstly, the incident travelling wave and the second backward travelling wave detected by the locator are adopted to determine the fault area. Next, the relevant travelling wave of the second backward travelling wave is defined and recognized based on the fault area. Then, the polarities of the second backward travelling wave and its relevant travelling wave are compared to determine whether the second backward travelling wave is reflected from the fault point or the remote-end bus. The proposed method only employs single modal travelling wave and is independent of bus configuration. Finally, the correctness and validity of the proposed method is tested and verified on a large number of EMTP based simulation cases.