Adaptive CFPREV Control for Cascading Commutation Failure Mitigation Considering Reactive Power Interaction

Advancing the firing angle implemented by the commutation failure prevention (CFPREV) is an effective method for commutation failure (CF), but the increase of reactive power consumption of local inverter would cause adverse influence on voltage at the ac busbar of adjacent HVDC systems due to the reactive power interaction, which may lead to the cascading CF in multiple HVDC systems. However, few researches focus on the coordinated control of CFPREV in multiple HVDC systems, thus a novel adaptive CFPREV control for cascading CF mitigation is proposed in this paper. Firstly, the influence of CFPREV on cascading CF and the limitation of existing control strategy are analyzed. Then traditional constant gain factor of CFPREV is replaced by an adaptive parameter, the value of which is determined based on the real-time extinction angles of other HVDC systems and the degree of reactive power interaction. Simulations implemented based on the multi-infeed HVDC system model in PSCAD/EMTDC verify the effectiveness and advancement of proposed control strategy compared with the existing method.