雷击舰船金属桅杆的线缆耦合效应试验研究

Experimental study on cable coupling effects of lightning strikes on a metal mast

[目的]旨在通过试验研究探索金属桅杆遭受雷击时内部线缆的耦合响应特性问题。[方法]搭建桅杆内部线缆系统雷电感应耦合试验平台,测量同轴线缆、两芯单屏蔽线缆及多芯双屏蔽线缆在4种端接负载特性(芯线两端均开路、芯线近地端接负载、芯线远地端接负载以及芯线两端接负载)下受模拟雷电流干扰产生的感应电压,并从时域和频域的角度分析感应电压与屏蔽效果受负载特性变化的影响规律。[结果]结果表明,4种端接负载情况下,3种线缆的感应电压均在芯线远地端接负载的情况下达到最大值;当芯线近地端接负载时,感应电压的主要频段大于雷电流,而在其他负载特性下两者相近;内屏蔽层接地能够降低感应电压峰值,但不影响频率响应的主要频段,芯线两端开路或远地端接负载时电压峰值的削弱最明显,分别降为内屏蔽层未接地时的59.3%和77.2%;3种线缆的感应电压峰值有较大差异,而上升时间和半峰值时间无明显区别。[结论]研究成果揭示了雷击舰船金属桅杆时端接负载特性对线缆耦合感应电压的影响规律,也为后续开展耦合效应计算提供了基础数据支撑。

[Objective]This paper carries out an experimental study on the coupling response characteristics of the internal cables of a metal mast when struck by lightning.[Method]A lightning induction coupling test platform is built for the cable system inside the mast.The induced voltages of the coaxial cables,two-core single shielded cables and multi-core double shielded cables are measured under four kinds of termination load characteristics(open circuit at both ends of core wire;end of core wire near to the ground connected to the load;end of core wire far from the ground connected to the load;and both ends of core wire connected to the load).From the perspective of time domain and frequency domain,an analysis is made of the influence of load characteristics on the induced voltage and shielding effects.[Results]The induced voltage of the cable reaches its maximum value when the far ground terminal is grounded by the load.When the near ground terminal is grounded by the load,the main frequency band of the induced voltage frequency response exceeds the light-ning current,whereas they are similar under other load characteristics.Grounding the inner shielding layer can reduce the peak value of the induced voltage,but does not affect the main frequency band of the frequency re-sponse.The voltage peak value is most significantly reduced when both ends of the core wire are open-circuited or when the end of the core wire far from the ground is connected to the load(approximately 59.3%and 77.2%of the value when the inner shielding layer is ungrounded).In addition,the induced voltage peaks of the three types of cables exhibit considerable differences.However,the rise time and half-peak time of the induced voltage for each cable show insignificant differences.[Conclusion]This study reveals the influence of terminal load characteristics on cable coupling induced voltage when lightning strikes the metal mast of a ship,as well as providing basic data support for the subsequent calculation of the coupling effect.