Recovery Characteristics of RB-IGCT and Its Low Reactive Power Application in Hybrid Commutated Converter Based HVDC

Due to the limitation of the recovery characteristics of thyristors, the minimum extinction angle of traditional line commutated converter based high voltage direct current (LCC-HVDC) system is generally 12°, which requires the system to be equipped with expensive and large reactive power compensation equipment. Hybrid commutated converter (HCC) based on reverse blocking integrated gate commutated thyristor (RB-IGCT) with better recovery characteristics can operate at ultra-low extinction angle. This article first conducts an in-depth mechanism study on the recovery process of RB-IGCT under HCC conditions. Then, the differences in the recovery process of RB-IGCT under different conditions are analyzed through experimental design. On this basis, a 6-RB-IGCTs component and a ±10 kV/1 kA HCC system are designed. The ability of RB-IGCT to operate with low reactive power has been fully verified through component level experiments and system level experiments. Finally, the reactive power optimization capability of HCC operating at ultra-low extinction angle is analyzed through PSCAD/EMTDC simulation calculation. The application of RB-IGCT with better recovery characteristics in HCC is of great significance for optimizing reactive power configuration in HVDC systems.