柔性直流联接变阀侧断路器功能定位及必要性分析

Analysis of Functional Orientation and Necessity of Circuit Breaker at Valve Side of VSC-HVDC Connection Transformer

为了确保换流阀安全可靠运行,云南异步联网工程柔性直流单元首次在联接变阀侧设计了交流断路器,当系统发生短路故障且联接变交流进线断路器拒动时,可以通过该断路器切除短路故障。仿真结果表明,联接变阀侧断路器在发生直流极间短路故障且交流进线断路器拒动的极端情况下能快速切断故障电流,流过桥臂的短路电流的热效应累计值在设备耐受范围内,可保证子模块安全运行。

In order to guarantee the security and reliability operation of converter valve,the AC circuit breaker at valve side of connection transformer is designed in the VSC-HVDC unit of Yunnan asynchronous grid connection project at the first time.During the occurrence of system short circuit fault and the refused action of the AC inlet line circuit breaker of the connection transformer,the short circuit fault can be cut off by the circuit breaker.Simulation results show that the circuit breaker at valve side of connection transformer can quickly cut off the fault current under the extreme circumstances of both the occurrence of DC interpolar short circuit fault and the refused action of the AC inlet line circuit breaker.The cumulative value of thermal effect of the short current through the bridge arm is within the tolerance range of the equipment,which guarantees the security and reliability of the sub-module.