一种基于晶闸管的新型混合式直流断路器

A New Hybrid DC Circuit Breaker Based on Thyristors

为响应“碳达峰、碳中和”的宏伟目标,加快柔性直流输电技术的发展势在必行。混合式直流断路器是保证柔性直流电网安全运行的关键设备,用于实现直流侧故障分断,但现有拓扑大多采用IGBT作为开关元件,成本高且技术难度大。对此,提出一种基于晶闸管的新型混合式直流断路器。该断路器主要采用晶闸管代替IGBT实现电路状态的切换,大大降低了断路器成本和技术难度,此外该断路器还具备预充电以及自适应重合闸功能,为断路器的大规模应用奠定了良好的基础。针对所提断路器的工作过程进行了详细的解析和理论推导,在PSCAD/EMTDC中搭建了单端等效和四端直流电网的仿真模型对其进行仿真验证,并与典型直流断路器进行性能对比。仿真结果证明了所提直流断路器的可行性,并表明在具备相近性能的基础上所提直流断路器的成本相较于典型直流断路器得到大幅降低。

In response to the grand goal of“carbon peaking and neutrality”,it is imperative to accelerate the development of flexible DC transmission technology.The hybrid DC circuit breaker(DCCB)is a key device to ensure the safe operation of the flexible DC power grid,and is used to realize fault isolation on the DC side.However,in most of the existing topologies,IGBTs are used as switching elements,which are costly and technically difficult.Therefore,a new hybrid DCCB based on thyristors is proposed in this paper.The circuit breaker mainly uses thyristors instead of IGBTs to switch the circuit state,which greatly reduces the cost and technical difficulty.In addition,the circuit breaker also has the functions of pre-charging and adaptive reclosing,which lays a good foundation for the large-scale application of the circuit breakers.Moreover,a detailed analysis and theoretical derivation of the working process of the proposed circuit breaker is carried out.Simulation models of single-ended equivalent and four-terminal DC power grids are built in PSCAD/EMTDC.The proposed circuit breaker is analyzed and verified in the simulation models,and the performance is compared with the typical circuit breakers.The simulation results verify the feasibility of the proposed circuit breaker and show that,on the basis of similar performance,the cost of the proposed DCCB is greatly reduced compared with the typical DCCBs.