多端口机械式直流断路器的动作策略与参数优化

Operation Strategy and Parameter Optimization of Multi-port Mechanical DC Circuit Breaker

常规两端口直流断路器(DCCB)成本高、体积大,不适于在城市直流配电网中应用,而多端口DCCB被认为是一种有效的解决方案。然而,多端口DCCB需要应对更加复杂的电流开断工况,如单条或多条故障线路的同时隔离、负荷线路的灵活切除。考虑到混合式DCCB的通态损耗及常规机械式DCCB的固有缺点,以双电容构建主开断支路,提出一种多端口机械式DCCB拓扑,研究了其应对各种电流开断工况的换流原理和各组件动作策略,并给出了主开断支路的参数优化方法。基于PSCAD/EMTDC仿真平台的算例分析表明,文中的多端口机械式DCCB可以有效降低预充电容及其充电系统的耐压水平要求,亦可仅利用1条主开断支路实现任意进出线的电流开断。

The conventional two-port DC circuit breaker(DCCB)is expensive and bulky,and it is not suitable for the application in urban DC distribution networks,while the multi-port DCCB(MP-DCCB)is considered as an effective solution.However,the MPDCCB needs to deal with more complicated current interruption conditions,such as the simultaneous isolation of single or multiple fault lines and the flexible removal of load lines.In addition,considering the on-state loss of hybrid DCCBs and the inherent shortcomings of conventional mechanical DCCBs,a multi-port mechanical DCCB topology is proposed by using double capacitors to construct the main interruption path.The current commutation principle and the operation strategy of each component dealing with various current interruption conditions are studied,and the parameter optimization method for the main interruption path is given.The simulation results based on PSCAD/EMTDC indicate that the proposed multi-port mechanical DCCB can effectively reduce the withstand voltage level requirements of the pre-charging capacitor and its charging system,and it can also use only one main interruption path to realize the current interruption of any incoming and outgoing lines.