A Coordinated Control Strategy for Fault Ride-Through of Wind Farm Integration Based on VSC-HVDC

This study analyzes the structure property and operating characteristics of modular dynamic braking resistor(DBR) circuits in detail, and proposes a novel coordinated control strategy. This strategy combines modular DBR circuit control method with AC-voltage frequency increase or magnitude reduction method, applying to hybrid wind farms equipped with doubly-fed induction generators(DFIG) and squirrel cage induction generators(SCIG) for fault ride-through(FRT). To make full use of wind turbine generators'(WTGs) own performance characteristics, the limits of AC-voltage frequency increase or magnitude reduction at the point of connection of wind farm are designed according to grid code requirements and the operating characteristic of WTGs. Through power reduction of WTGs, further reductions in rated capacity of braking resistor, which may bring lower costs of DBR and better FRT effects, can be achieved. Simulation based on actual parameters from Nanao VSC-HVDC demonstration project and conducted in PSCAD/EMTDC validated the correctness and effectiveness of the proposed coordinated control strategy.