Active arc suppression based MMC-HVDC DC fault adaptive reclosing

Abstract

DC fault arcs continue to burn for a certain period under line residual energy (LRE) excitation, and existing DC fault reclosing has to wait for the DC arc to extinguish, resulting in a slow system recovery due to the long arc dissociation time. To address this problem, adaptive reclosing with active arc suppression (AAS) is proposed to speed up fault recovery. Firstly, a strategy is given for coordinating DC circuit breakers to quickly control the ground switch (GS) to switch between input and output states. Secondly, the positive effect of GS changing the line endpoint characteristics to achieve the AAS function on reducing the LRE content is revealed. In addition, a multiple AAS coordination method is given for different DC arc extinguishing speeds. Further, after each AAS, the voltage difference between permanent and non-permanent faults is mapped using the Pearson correlation coefficient to determine non-permanent faults. Compared with other typical reclosing, the proposed adaptive reclosing can actively shorten the arc dissociation time, reduce the power outage time to 13.5%–30%, which effectively improves the successful probability of fault reclosing, and prevents the MMC from restarting under non-permanent fault.