雷击桁架桥梁时雷电保护系统中瞬态电流分布的计算方法

Calculating Transient Current Distribution of Lightning Protection System of a Truss Bridge

针对由雷击引起的电磁干扰问题,提出了一种用于快速计算桁架桥梁各分支导体中雷电流分布的方法。该方法首先对桁架桥雷电防护系统上的每根导体用传输线进行等效,忽略导体之间的耦合作用后,整个桁架桥防雷系统等效为由传输线组成的无耦合电网络,然后在频域进行求解,并通过快速傅里叶逆变(IFFT)技术得到雷电防护系统中电流分布的时域解。为了验证算法的有效性,采用文中方法与其他文献中的方法分别对同一问题进行了仿真计算,结果表明:本方法在解的精度上与其他方法相近,但在求解速度、运算量两方面明显优于其他方法。本方法为快速获取桁架桥梁内部雷电电磁场分布奠定了基础,是分析、评估桁架桥内部雷电防护等级(LPL)的一种行之有效的方法。

EMI problems caused by lightning struck truss bridge are concerned extensively. A fast method for calculating the transient current distributions of LPS(lightning protection system) of truss bridge is designed. First, the transmission line model is established to model the each branch conductor of LPS, with ingnoring the electromagnetic coupling between conductors, and the LPS of truss bridge is modeled as transmission line network without electromagnetic coupling. Then, the model is calculated in frequency domain, and the transient response of a LPS is obtained by using IFFT. In order to verify accuracy and efficiency of the presented method, the results obtained by presented method and methods in other literatures are compared, the difference in results is small, and time consuming is short. The method in this paper lays the foundation for transient lightning electromagnetic fields calculation and it is effective to evaluate the LPL of truss bridge.