基于直流高速开关的换流站在线投退策略

特高压多端直流工程中，采用直流高速开关(HSS)配合全/半桥混合模块换流阀的方式来实现直流故障清除和换流站在线投退是现有技术水平下的较佳选择，但HSS极弱的直流电流分断能力对控制保护设备提出了苛刻要求，且该方式下的换流站在线投退策略尚未见报道。基于HSS的电气特性和混合模块换流阀的能力，分析了多端直流系统中HSS的配置原则并设计了HSS典型电路；研究了基于HSS的换流站在线投退策略和多电压源换流器(VSC)换流站协同充电方案；为了保障系统和设备安全，提出了HSS的详细保护策略和动作结果。所提策略均已在昆柳龙混合直流工程中进行了应用，研究结果可为多端直流工程的单站投退方案提供借鉴和参考。

Online entry and exit control strategy for single converter station based on DC high speed switch

In multi-terminal UHVDC(Ultra High Voltage Direct Current) projects, it is a good choice to rea-lize DC fault clearing and online entry and exit of converter station by using DC HSS(High Speed Switch) combined with full/half-bridge hybrid-module converter valves. However, the weak DC current breaking capacity of HSS puts forward strict requirements for the control and protection equipment, and the online entry and exit strategy of converter station under this mode has not been reported yet. Based on the electrical characteristics of HSS and the ability of hybrid-module converter valves, the configuration principle of HSS is analyzed and the typical circuit of HSS is designed. Then, the online entry and exit strategy for converter station based on HSS and the cooperative charging scheme of multiple VSC(Voltage Source Converter) converter stations are studied. Finally, in order to ensure the safety of system and equipment, the detailed protection strategies of HSS and their action results are proposed. All of the proposed strategies have been applied in KLL hybrid DC project, and the research results can provide reference for single station entry and exit scheme of multi-terminal DC projects.