架空配电线路感应过电压计算方法适用性研究

Study on the Applicability of Calculation Method of Lighting Induced Overvoltage on Overhead Distribution Lines

针对现有雷电感应过电压数值计算模型工程适用性不强的问题,分析了雷电感应过电压产生的物理过程,基于时变电磁场理论提出了架空线路雷电回击入射场与感应场的电磁耦合关系,推导得出了架空线路雷电感应过电压时域波形的解析计算模型。计算分析了雷电流幅值、回击速度、雷电流波形对架空配电线路感应雷过电压时域波形的影响规律,结果表明:随着回击放电速度的增加,相同条件下感应过电压幅值有所降低且波头时间增加,当回击电流波前时间增加时,感应过电压幅值也显著降低。该模型解决了传统规程法忽略电磁分量且无法分析工程约束条件对感应过电压波形影响的问题。

Aiming at the problem of insufficient project applicability of current numerical models for lighting induced overvoltage calculation,the physical process of lighting induced overvoltage generation is analyzed in this paper.Based on the transient electromagnetic theory,the electromagnetic coupling of incident field and induced field of overhead distribution line lightning return stroke is proposed,and the analytic calculation model of the time domain waveform of overhead distribution line lightning induced overvoltage is deduced.The influence of lightning amplitude,return stroke speed,and lightning waveform to the time domain waveform of overhead distribution line lightning induced overvoltage is calculated and analyzed.The result shows that the lightning induced overvoltage amplitude will decrease a little and the wavefront time will increase under the same conditions with the increase of return stroke speed,and that the lightning induced overvoltage amplitude will decrease remarkblely with the increase of return stroke wavefront time.The model in this paper solves the problem that the traditional regulation method neglects the electromagnetic component and cannot analyze the influence of project constraint condition to the lighting induced overvoltage waveform.