短路工况下柔直换流站直流场内瞬态电场预测分析

Prediction and Analysis of Transient Electric Field in DC Yard of Flexible Converter Station Under Short-Circuit Conditions

柔性直流换流站在发生短路故障时会产生瞬态强电磁场,对换流站内的二次设备产生潜在影响。针对定海换流站短路试验时二次设备处的电场骚扰问题进行了系统研究,分析了短路故障时直流场内关键节点的电位,建立了直流场内设备的三维模型。考虑直流断路器分断时的时变拓扑结构,将获得的直流场内各节点电位函数作为电准静态场求解区域的第1类边界条件,分别计算了3种短路工况下直流断路器周围二次设备处的电场分布。研究结果表明,二次设备处电场强度最高可达33 kV/m,上升下降沿最快为40μs;电场强度的大小由空间布局和电压幅值共同决定,电场强度波形与电压波形上升下降沿一致。

In the case of short-circuit fault,the flexible DC converter station would produce transient yet strong electromagnetic field,which would impact on the secondary equipment in the converter station.In this paper,the problem of electric field disturbance at the secondary equipment in the short circuit test of Dinghai converter station was studied systematically.The potential of the key nodes in the DC field was analyzed,and 3D model of the equipment in the DC field was established.Considering the time-varying topological structure of the DC circuit breaker,the potential function of each node in the DC field was taken as the first boundary condition of the electric quasi-static field solution area,and the electric field distribution of the secondary equipment around the DC circuit breaker under three kinds of short-circuit conditions was calculated accordingly.The following facts were revealed by the simulation results:the maximum electric field strength is 33 kV/m;the maximum rise and fall edge is 40μs;the electric field strength could be determined by the spatial layout and voltage amplitude;and the electric field strength waveform would be consistent with the rise and fall edge of the voltage waveform.