Turn-off Control Method of the Hybrid Commutated Converter Based on Fault Prediction

With the continuous construction of “Desert-Gobi Desert-Wasteland” new energy bases in northwest China, energy cross-regional transportation technology has become increasingly critical. Despite the fact that the transmission technology of line commuted converter high voltage direct current (LCC-HVDC) plays a crucial role depending on long-distance, large-capacity, and low-loss transmission advantages, its inherent commutation failure (CF) remains to be solved urgently. Nevertheless, Tsinghua University has proposed the technology of hybrid commutated converter (HCC) based on the reverse blocking integrated gate commutated thyristor (RB-IGCT), which can completely solve this problem. In terms of the HCC, this paper proposes an active turn-off control method based on fault prediction. First, the fault prediction means used in the turn-off control method and its principle of resisting commutation failure are introduced; next, it is transformed on the basis of the original LCC control system to enable it to be the control system applicable to HCCs; last, based on the modified model, fault simulation is carried out, and the effect of resisting commutation failure is obtained through the turn-off control method of the HCC based on fault prediction.