中文摘要：

接地装置冲击特性是影响输电线路耐雷水平和雷击跳闸率的重要因素．将电力系统接地分析软件CDEGS中的快速傅里叶变换模块FFTSES和电磁场频域分析模块HIFREQ相结合．通过引入Visacro-Alipio土壤频变公式，建立可以考虑土壤电参数频变性的接地装置冲击特性的数值计算模型．利用所建模型重点仿真分析不同土壤电阻率和不同冲击电流波形下土壤电参数频变特性对接地装置有效长度的影响情况．仿真数据分析表明，考虑土壤频变性时接地装置的有效长度与不考虑土壤频变性时的有效长度相比有一定减小，并且在高土壤电阻率下减小程度更明显．

英文摘要：

Impulse charactersitic of grounding devices was the important factor of lightning withstand level and lightning trip-out rate of transmission line. Based on HIFREQ program and FFTSES program in grounding pow- er system analysis software CDEGS, this paper presented a grounding system impulse characteristic modeling considered soil frequency-dependence, especially, the Visacro-Alipio soil frequency-dependence formula has been introduced. The impact of the soil frequency-dependence on the effective length of the grounding device in different initial soil resistivity and different impulse current waveform was analyzed. The calculating results showed that when considering soil frequency-dependence, the impulse effective length would be shorter, espe- cially for the grounding devices buried in high resistivity soil.