换相失败交流系统临界电压计算

Calculation on Critical Voltage of AC System for Commutation Failure

讨论了交流系统电压对直流换相面积的影响,推导出直流换相失败对应交流系统临界电压,并计算得到三相故障典型工程换相失败交流系统临界电压。以实际工程为算例,建立含大型调相机及实际直流模型的特高压交直流混联电网计算平台,以1 ms时间间隔计算交流系统故障,得到直流系统换相失败对应交流临界电压。将理论推导结果与仿真计算平台得到的临界电压进行对比,理论与实际工程结果得到相互验证,对将来电网规划、调度运行、结构优化、新增动态无功补偿设备防止换相失败具有较强理论指导意义。

This paper first discusses the influence of AC system voltage on DC commutation area,deducing the critical voltage of AC system corresponding to commutation failure of HVDC,and calculating to obtain the critical voltage of typical engineering with three-phase fault for commutation failure.And then,the paper takes the actual project as an example to establish an UHV AC-DC hybrid power grid computing platform with large phase regulator and actual DC model,and also calculates the AC system failures at 1 ms intervals,obtaining the critical voltage of AC system corresponding to commutation failure of HVDC.Finally,the paper compares the theoretical results with the critical voltage obtained by the simulation platform,with theoretical and practical engineering results mutually verified,which has a strong theoretical guiding significance for future power grid planning,dispatching,operating,structural optimization and adding of new dynamic reactive compensation device to prevent commutation failure.