Fault ride‐through control based on voltage prioritization for grid‐forming converters

Abstract

AbstractThis paper discusses that the existing grid codes on the fault ride‐through (FRT) operation have certain complications to be implemented in the grid‐forming (GFM) converters. In particular, they do not provide a clear guidelines on the suitable prioritization of the positive‐ and negative‐sequence currents needed for a desired voltage profile during FRT operation. To address this challenge, two FRT controls which are based on (i) voltage balancing priority, and (ii) voltage magnitude priority are investigated for GFM converters. The former gives priority to the elimination of negative‐sequence voltage, while the remaining converter's capacity is used to increase the positive‐sequence voltage. On the contrary, the latter prioritizes the increase of positive‐sequence voltage, while it tries to reduce negative‐sequence voltage by using the remaining converter's capacity. The dynamic performances of these two FRT controls are thoroughly discussed, and the simulation results show that depending on the desired voltage profile during fault, one of them can be implemented.