Offshore Wind Integration to a Weak Grid by VSC-HVDC Links Using Power-Synchronization Control: A Case Study

In this paper, the application of a recently invented power-synchronization control is proposed for integrating a doubly fed induction generator (DFIG)-based offshore wind farm to a weak ac grid through a voltage-source converter (VSC)-based high-voltage dc link. The control strategy, along with the antiwindup techniques and the bumpless transfer between two different control modes, is elaborately discussed. Two different fault cases, namely, onshore and offshore faults are considered and the fault-ridethrough techniques are presented. In case of the onshore fault, both with-chopper and without-chopper solutions are investigated. For an offshore fault, a coordinated fault-ridethrough scheme is proposed when the offshore HVDC converter and the wind farm are in voltage-control modes. The entire study is carried out in a real-time digital simulator (RTDS) platform.