Research on Fault Ride‐Through Characteristics of Inverter‐Side Hybrid HVDC in Offshore Wind Farms

ABSTRACT This paper addresses issues in wind power DC transmission systems, such as difficulty in maintaining power delivery during rectifier‐side faults and frequent overvoltage occurrences during inverter‐side faults. A hybrid topology comprising a rectifier‐side MMC and an inverter‐side LCC‐MMC configuration is proposed, along with corresponding enhanced control strategies. The characteristics of the proposed hybrid HVDC under bilateral AC faults are investigated. Results indicate that during single‐phase faults on the rectifier side, the proposed model and control strategy can maintain transmitted power at 0.54 p.u. or higher, preventing power transmission interruptions. Compared to conventional control strategies for inverter‐side hybrid DC transmission systems, the minimum power transmission value increases by 11%. Under inverter‐side AC faults, wind power output can track power variations during the disturbance. During a single‐phase‐to‐ground fault, the DC voltage of the receiving‐end MMC is limited to within 1.13 p.u., and during a three‐phase short‐circuit fault, it is restricted to within 1.29 p.u., remaining below the safety threshold of 1.3 p.u. Consequently, the proposed system effectively ensures the long‐distance and reliable transmission of wind power, making it suitable for the dependable delivery of large‐scale offshore wind power.