Study on the excitation inrush suppression strategy of phase-selective switching converter with closing resis-tor switch considering dispersion

A detailed analysis of the excitation inrush current bias phenomenon in the event is carried out in the context of a certain time when charging of a converter is carried out in an ultra-high voltage DC project of the Southern China Power Grid to obtain the cause of the event, which is confirmed by RTDS tests. By analysing the relationship between the moment of closing of different auxiliary contacts and the intermittent angle of the excitation inrush current, the shortest input time at which the closing resistance can play a role in weakening the excitation inrush current is proposed at different moments of closing. Finally, considering the discrete nature of circuit breaker closing, the proposed closing resistor best access time and the best closing angle, the effectiveness of the proposed strategy is verified by simulation tests.