Analysis of response of VSC-based HVDC to unbalanced faults with different control systems

This paper investigates the dynamic performance of a VSC-HVDC system under unbalanced faults in ac systems. Three different control systems are presented and analyzed for the most common unbalanced fault, i. e. single-line-to-ground fault (SLGF) in PSCAD/EMTDC. Simulation results show that the system resumes normal operation after fault clearing using all three control systems, among which the third control system produces the best transient performance.