雷电流波形参数检测视角下±800kV直流输电线路导线绕击分析

Electromagnetic Analysis of Shielding Failure in ±800 kV DC Transmission Line in the Aspect of Acquiring Lightning Parameters

雷电流波形参数主要集中于雷电流上升沿,为分析雷击输电线路后各个行波通道暂态电流所含雷电流上升沿信息,从获取雷电流波形参数的视角,应用分布参数电路理论研究雷电绕击特高压输电线路的行波响应,分析在雷击闪络和未闪络情况下,注入导线的雷电流在诸电流通道中的电流行波波形。雷电绕击导线造成闪络的波过程可视为雷电流注入和闪络故障附加激励先后两次冲击在导线和绝缘子所引起的行波暂态响应。根据闪络冲击发生于雷电流冲击峰值之前和之后,将闪络分为波前闪络和波后闪络,于此两种闪络情况下,分析不同电流通道暂态电流所包含的雷电流波前信息。考虑了冲击电晕和杆塔对导线和绝缘子暂态电流波形的影响。分析和数字实验表明:绕击导线发生波前闪络情况下,导线暂态电流不含雷电流的峰值(参数);而波后闪络情况下,导线暂态电流含有雷电流的峰值(参数);无论是波前闪络还是波后闪络,绝缘子闪络电流均不含有雷电流上升沿信息,雷电流上升沿信息只含于导线暂态电流,故为了获取雷电流波形参数,须检测雷击点附近导线的电流行波。

Lightning at rise time contains most information of lightning waveform parameters.In order to analyze the information of lightning current at rise time in different traveling channels,the distributed resistance circuit theory was adopted to study the response of direct lightning strokes for acquiring lightning parameters and to analyze the traveling wave under the situation of lightning disturbance and flashover.The response of shielding failure causing flashover could be regarded as two impulses at different time in very short time-domain.The flashover occurring time was distributed at the rise time and the tail time of the lightning wave,and the transient currents in distinct traveling channels were utilized to analyze the lightning information in them.The effect of corona and tower grounding devices were thus considered.The analysis illustrates that the lightning information varies at flashover rise time and tail time of the lightning wave,the current of the insulator does not contain information of lightning rise time parameters,the transient current of line does not contain the amplitude of lightning when flashover occurs at rise time but contains the amplitude of lightning when flashover occurs at tail time.Then in order to obtain the accurate lightning parameters,the line currents around the lightning stroke point should be required.