适用于海上风场并网的混合多端直流输电技术研究

Offshore wind power integration using hybrid multi-terminal HVDC technology

针对海上风电并网的需求,提出了采用VSC换流器连接海上风场和弱受端交流系统,LCC换流器连接较强交流系统的混合多端直流输电系统拓扑结构,并对一个混合5端直流输电系统进行了详细研究。分析了5个换流器的电压电流控制特性,设计了直流系统控制策略,研究了系统在风速波动、逆变侧VSC和LCC分别出现三相短路故障以及直流线路故障时系统的动态响应特性。仿真结果表明所提出的混合多端直流输电系统具有较好的运行特性,可以适应海上风电并网的需求。

A hybrid multi-terminal HVDC （MTDC） which connects offshore wind farm and weak receiving AC system by using VSC and connects stronger AC system by adopting LCC is proposed to solve the issue of offshore wind farm interconnection. A five-terminal hybrid MTDC model system including a large capacity wind farm is set up in PSCAD/EMTDC, in which the corresponding control strategy is designed. The operational characteristic of the hybrid system is studied and the proposed control strategy is verified through simulation under various conditions, including the wind speed variation and three-phase short-circuit faults on VSC and LCC inverter side as well as faults at DC line. Simulation results show that the proposed hybrid multi-terminal HVDC system possesses favorable operation characteristics and is suitable for the offshore wind farm integration.