新型高压直流断路器的自供能控制策略

Self-powered control strategy of new HVDC circuit breaker

提出了一种新型混合式高压直流断路器的拓扑结构及其自供能控制策略。该新型断路器包括超快速机械开关、负载转移开关和主断路器等部件。负载转移开关和主断路器都是由增强型半桥子模块构成。通过所设计的控制策略,可以使子模块中的电容在正常工况下带电运行,进而可以为子模块中的IGBT提供驱动所需要的能量。该新型断路器存在启动充能模式、稳态运行模式和故障处理模式3种运行模式。针对上述3种运行模式分别提出了相应的控制策略。增强型半桥子模块是新型直流断路器的核心元件,给出了其关键参数的选取方法。在PSCAD/EMTDC仿真软件中搭建了四端直流电网模型,仿真结果验证了所提的新型高压直流断路器及其控制策略的可行性和有效性。

The topology of a new hybrid HVDC circuit breaker and its control strategy of self-powered capability are proposed.This new circuit breaker consists of ultra-fast mechanical switches,load commutation switches and main circuit breakers.The load commutation switch and the main circuit breaker are formed through the series of EHBSMs(Enhanced Half-Bridge Sub-Modules).By the corresponding control strategy,the energy stored in the EHBSMs can be used for IGBT triggering.The new circuit breaker can operate in three modes,namely the start-up mode,the steady-state operation mode and the fault handling mode.These three modes are analyzed in detail and the corresponding control methods are proposed.Besides,the selection method of the EHBSMs' key parameters is discussed.Finally,a four-terminal DC grid model is built in PSCAD/EMTDC simulation software.The simulative results verify the feasibility and effectiveness of the new HVDC circuit breaker and its control strategy.