State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources (North China Electric Power University), Beijing 102206, China
In order to further improve the defense capability of enhanced line commutated converter against the commutation failure, this paper proposes a new coordinated control strategy applied to the enhanced line commutated converter based high voltage direct current (ELCC-HVDC) system by combining the impedance shunt characteristics of the commutation circuit and the turn-off characteristics of the thyristor. This strategy is divided into the auxiliary commutation control and the active and reliable shutdown control. The former accelerates the commutation process and improves the commutation margin of the system; the latter reliably turns off the valve arm which exits the conduction, thus ensuring the physical conditions for the thyristor in the valve to recover the blocking ability. In addition, the electrical stress of the fully controlled device of the submodule using the proposed strategy is analyzed, and the optimal initial capacitor voltage is designed for it. The PSCAD/EMTDC simulation results show that the electrical stress of the fully controlled device of the submodule meets the theoretical analysis, and the new coordinated control strategy improves the commutation failure prevention ability of the ELCC-HVDC system.
ZHAO Chengyong, ZHAN Ruiqi, YE Yunxia, et al. Control Strategy of Enhanced Line Commutated Converter for Active Resistance to Commutation Failure[J/OL]. Automation of Electric Power Systems, http://doi. org/10.7500/AEPS20210409001.