A novel high-speed transient-based phase selector for AC transmission line connected to LCC-HVDC inverter station

Affected by commutation failure and fast control of line-commutated-converter (LCC) high-voltage direct-current (HVDC) inverter station, conventional phase selectors exist adaptability problems. In this paper, a novel faulted phase selector for AC lines connected to LCC-HVDC inverter station, based on the ratio of transient current energy, is proposed. Firstly, the inadaptability of conventional phase selection methods is briefly analyzed in this paper. Besides, the current relationship of the initial stage of the fault is immune to the commutation failure disturbance, and the current information of this stage is constructed as a transient energy ratio which is used to select the fault phase. On this basis, considering the weak amplitude characteristics of high-frequency signals, synchronous squeezed S-transform (SST) is introduced to process signals in this paper. PSCAD/EMTDC simulation results verify that the proposed phase selector can effectively avoid the DC-side commutation failure and control influence, achieve fast and reliable phase selection, and is weakly affected by the fault resistance, fault distance, initial fault angle, and noise interference.