Short-circuit Current Analysis for AC Fault on Sending End Subsystem of Wind Farms Connected to MMC-HVDC

The sending end systems of offshore wind power connected through MMC-HVDC consist solely of power electronics, presenting complex fault characteristics. This study introduces a short-circuit current calculation method utilizing the symmetric component method and analyzes the fault response of the system under MMC voltage regulation strategy. The impact of variables such as fault location and the phase of the wind farm output current on each electrical parameter during a short-circuit is examined. The voltage regulation strategy is taken into account in the short circuit current calculation method and the mechanism of the conventional voltage regulation strategy in this new fault scenario is analyzed in detail. A simulation model, created in PSCAD, effectively verifies the accuracy of the proposed calculation method.