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为了研究高铁信号系统多芯扭绞电缆暂态过电压特性,指导高铁信号电缆的暂态过电压防护,该文分析了现有电缆暂态模型的不足,提出一种改进计算方法。该计算方法可分为单个扭绞周期长度电缆级联传输线参数计算和电缆多导体传输线时域宽频等效建模两个方面,考虑了芯线间的临近效应和集肤效应的影响以及电缆的扭绞特性。通过与雷电冲击下的转移阻抗特性和传递特性试验对比验证了建模方法的有效性。针对高铁常用的双四线组扭绞信号电缆,建立了其宽频模型,分析了电缆屏蔽接地方式和备用芯线接线方式对电缆芯线雷电暂态过电压特性的影响,结果表明:双端接地方式能明显限制芯线对地暂态过电压幅值;备用芯线与屏蔽层连接并接地可一定程度上降低工作芯线对地暂态过电压幅值。
In order to study the transient overvoltage characteristics of multi-core twisted-pair cables in high-speed railway signaling system and to guide the transient over-voltage protection of high-speed railway signal cables, this paper analyzes the shortages of the existing cable transient models and proposes an improved calculation method. The calculation method can be divided into the following two aspects: the calculation of the parameter of cable cascading transmission line with single twisted cycle length and the equivalent modeling of cable multi-conductor transmission line in time domain. Considering the effect of proximity and skin effect between cables and the influence of cable Twisting characteristics. The effectiveness of the modeling method is verified by comparing the transfer impedance and transfer characteristics with the lightning impulse. Aiming at the double quadruplex twist signal cable commonly used in high-speed railway, a broadband model was established and the influence of cable shielding grounding mode and backup wiring connection on the transient overvoltage characteristics of cable core lightning was analyzed. The results show that: Way can significantly limit the core-to-ground transient over-voltage amplitude; backup core wire and the shield connected to ground and to some extent reduce the core-to-ground transient over-voltage amplitude.