A Virtual Resistance-Capacitance Control Strategy for Mitigating Consecutive Commutation Failures in Weak Receiving-End HVDC Systems

Abstract

In view of the high susceptibility of weak receiving-end High-Voltage Direct Current (HVDC) systems to consecutive commutation failures during AC faults on the inverter side, a novel virtual resistance-capacitance control strategy is proposed. This strategy is designed to suppress the occurrence of consecutive commutation failures and enhance the stability of weak receiving-end HVDC systems. Incorporating the Voltage Dependent Current Order Limit (VDCOL), this paper analyzes how virtual resistance and capacitance regulate the DC current command by exploiting their respective current-limiting and voltage-stabilizing attributes. A novel VRC-based strategy is then developed to mitigate consecutive commutation failures, complemented by the derivation of the governing equation for the DC current reference value. Subsequently, the analytical formulas for calculating the virtual parameters within the proposed control strategy are derived. Furthermore, the optimal values for the virtual resistance and virtual capacitance are determined to achieve the best suppression performance against commutation failures. Finally, a weak receiving-end LCC-HVDC system model is constructed in the PSCAD/EMTDC environment. The simulation results verify that the proposed virtual resistance-capacitance control strategy effectively suppresses consecutive commutation failures during AC system faults on the inverter side.