VSC-LCC型混合直流输电系统启动控制策略研究

针对VSC-LCC型双端混合直流输电系统拓扑，结合其系统特殊性提出了一种基于极性切换的启动控制方案。建立了VSC-LCC型双端混合直流输电 系统拓扑及其数学模型；在VSC换流器整流侧采用直接电流控制方法，在LCC换流器端逆变侧采用定直流电压控制方法的基础上，针对该系统潮流单向 流动性的限制问题，在LCC换流器端直流侧采用极性切换的启动控制策略；在PSCAD/EMTDC环境下建立了该系统的模型，验证了设计的启动控制策略。 仿真结果表明，该启动控制策略能有效抑制启动过程中的过电流和过电压，保证系统平稳地过渡到额定运行状态，达到了良好的启动控制效果。

Research on Startup Control Strategy for VSC-LCC Hybrid HVDC System

The paper proposes a start-up control strategy based on polarity switching for VSC-LCC dual-ended hybrid HVDC system. Firstly， the topology for the VSC-LCC dual-ended hybrid HVDC system and its mathematical model is established. Then， aiming at the limitation of the one-way flow of the system load flow， the polarity switching based start-up control strategy is adopted on the DC side of the LCC converter， by using DC control on the rectifier side of VSC converter and constant DC voltage control on the inverter side of LCC converter. Finally， a model for the system is built using PSCAD/EMTDC software to verify the effectiveness of the startup control strategy. The simulation results show that the strategy can effectively restrict the over- current and over-voltage during the startup procedures， ensuring the smooth transition to the rating state of the system.