研制了一套能够同时测量线缆皮线和芯线感应电流的试验系统, 研究自然闪电条件下敷地线缆的耦合问题。结果表明：不同位置处的线缆皮线感应电流波形基本一致, 但幅值存在一定差异, 说明感应电流空间分布不均匀; 所测线缆芯线和皮线感应电流的时域波形和频谱比较相似, 能量集中在1 kHz~1 MHz之间; 正负地闪芯线感应电压波形均为单一脉冲型, 波形持续时间10~49 μs; 正地闪线缆感应电压的幅值范围及幅值平均值都大于负地闪相应结果, 说明正地闪产生的线缆耦合作用大于负地闪; 不同雷电过程的线缆感应电压幅值与磁感应强度有较小的相关性, 而同一雷电过程则基本成线性关系; 正地闪线缆感应电压波形持续时间、半峰值宽度、10%~90%上升时间的范围及均值都比负地闪的要大。

A test system capable of simultaneously measuring the induced currents in the cable shield and inner conductor was developed to study the coupling problem of the cable on the ground under the natural lightning condition. The results show that: Waveforms of cable induced currents in the cable shield at different positions are basically the same, but the amplitudes are different which shows that the spatial distribution of the induced currents is not uniform. The time-domain waveforms and frequency spectrums of the induced currents measured in the inner conductor and cable shield are alike and the energy is concentrated between 1 kHz and 1 MHz. The induced voltage waveforms in the inner conductor of the positive and negative cloud-to-ground lightning are all single-pulse waveforms with a duration of 10-49 μs. The amplitude and their mean value of the cable induced voltages of the positive cloud-to-ground lightning are greater than the corresponding results for negative cloud-to-ground lightning, indicating that the cable coupling effect of positive cloud-to-ground lightning is greater than that of the negative cloud-to-ground lightning. The cable induced voltage amplitude and magnetic flux density of different lightning processes have small correlation and the same lightning process is basically linear. The cable induced voltage waveform duration time, the half-peak width, the range of the 10%-90% rise time and their average value of the positive cloud-to-ground lightning are all greater than those of the negative cloud-to-ground lightning.