Coordinated CFPREV Control for Cascading Commutation Failure Mitigation in Multi-infeed HVDC Systems

The commutation failure prevention (CFPREV) is widely applied for commutation failure (CF) mitigation, but the inherent defect that the reactive power consumption of inverters would be increased when the mechanism is triggered makes its performance becomes worse in multi-infeed HVDC systems due to the reactive power interaction between inverters, which may even cause the cascading CF. However, very few studies have devoted to the coordination of CFPREV in multiple HVDC. In this paper, a novel coordinated CFPREV control is proposed for cascading CF mitigation based on the limitations of traditional control. Firstly, a comprehensive indicator that represents the real-time voltage states of adjacent inverters is presented. Then the comparison between local voltage and adjacent voltage states is introduced into the original control to develop the coordinated CFPREV. Simulation results verify the advancement of proposed coordinated strategy on cascading CF mitigation, since CFPREV in multiple inverters are controlled considering the voltage states of adjacent HVDC and the reactive power interaction.