A novel fault-location method for VSC-MTDC transmission lines based on EMTR

This paper presents a novel method for locating faults on VSC-MTDC transmission lines using electromagnetic time reversal (EMTR) theory. A method named "First fault-segment, Second fault-location" is proposed. The observed currents are time-reversed and back-injected into the simulation system, which equals to the actual system. In this procedure, a fault is not necessary to be assumed in the simulation system. After fault segment has been screened, the fault location can be verified with minor calculation burden. Moreover, the performances of the EMTR-based technique are discussed under different time-asynchronous cases. The simulation test cases are: a five-terminal VSC-HVDC modified from the China Nan-au demonstration project. Considering the effects of protection and control system, the proposed method presents its straightforward application with low sampling rates and ultra-short time-windows, and robustness against fault type and fault impedance. (paper)