中压直流配电系统故障过电压水平分析

摘要

为解决珠海"互联网+"柔性直流配电系统的绝缘配合问题,运用PSCAD/EMTDC仿真软件搭建了三端柔性直流配电系统模型,对主换流器区域和直流线路区域的典型故障事件、保护动作后的系统关键位置过电压水平进行仿真,并通过同类故障点间的比较得到每种故障事件下的过电压最大水平.仿真结果表明,主换流器区域的桥臂电抗器阀侧接地故障、直流电抗器阀侧极间短路故障是过电压较严重的2种故障情况;直流线路区域的极间短路故障发生时,主换流器区域过电压较直流线路区域更严重;主换流器区域的联接变压器阀侧单相接地故障和直流线路区域的首端单极接地故障特性较相似.%In order to solve the problem of insulation coordination of Zhuhai internet plus flexible DC power distribution system, this paper uses PSCAD/EM TDC simulation softw are to build a three-terminal flexible DC pow er distribution system model for making simulation on overvoltage levels of key locations of the system after some typical fault events occur and protections act in the main converter area and the DC line area.M eanw hile, it obtains the maximum overvoltage level under each fault event by comparison betw een similar fault points.The simulation results show that ground fault at the converter side of the bridge arm reactor and interelectrode short circuit fault at the converter side of the DC reactors in the main converter area are faults w ith severe overvoltage.As the interelectrode short circuit fault occurs in the DC line area, the overvoltage of the main converter area is more serious than that of the DC line area.The single-phase ground fault at the converter side of the coupling transformer in the main converter area is similar to the monopole grounding fault at the head of DC line in the DC line area.