埋地电缆雷电感应过电压观测和分析
Observation and analysis of lightning induced overvoltage on buried cables
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摘要: 通过测量自然闪电条件下埋地电缆的雷电感应过电压，探讨了不同类型电缆屏蔽层对芯线上感应过电压的影响。结果表明：电缆屏蔽层具有明显降低雷电感应过电压的作用；对同一次自然闪电，相对于电源电缆，控制电缆和信号电缆上感应电压脉冲波形峰峰值分别为65%和26%。在选取的起始脉冲时间段内，电缆感应过电压正、负峰值的绝对值同时增大或减小，具有一定的对应关系。钢带屏蔽层能够有效抑制控制电缆感应过电压400 kHz～1 MHz的频率分量，铜编织带屏蔽层对信号电缆感应过电压50 kHz以下频率分量的削弱效果明显。总体来看，铜编织带比钢带具有更好的屏蔽效果。Abstract: The experiments have been conducted about lightning electromagnetic pulse (LEMP) coupling to buried cables in the depth of 0.5 m. The test system and the measurement method are both introduced, and the lightning induced overvoltages at the end of the buried cables are analyzed. The cables are used in automatic weather stations, i.e. the power cable without shielding layer, the signal cable with a braided copper shield and the control cable with a steel shield. Relative to the peak voltage induced on the power cable, the peak voltages induced on the control cable and the signal cable are 65% and 26% respectively. The peak induced overvoltage of the three cables has a similar trend in the initial stage of the LEMP. The steel belt shielding layer can effectively reduce 400 kHz～1 MHz componen
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Key words:
- lightning electromagnetic pulse /
- coupling /
- buried cables /
- induced overvoltage /
- shielding
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