基于雷电流注入的圆柱表面电流分布仿真研究

Simulation Research on Surface Current Distribution of Circular Cylinder Based on Lightning Current Injection

雷电间接效应通过外部雷电能量耦合进入腔体内部,在设备或系统连接电缆上感应产生过电流和过电压而发生作用,腔体内部场可由表面电流透射产生。针对雷电间接效应作用下圆柱腔体表面电流分布规律不完善的问题,采用基于传输线矩阵法的3D电磁仿真软件CST MICROSTRIPES工作室分别对有限长规则圆柱和有限长带弧表面圆柱进行仿真分析。仿真结果表明:在雷电流脉冲注入情况下,规则圆柱横向电流沿轴向分布较为均匀,但前后边缘处较大;带弧表面圆柱横向电流沿轴向(半径小处为头部)呈衰减趋势,圆柱表面曲率半径越大,衰减程度越小;规则圆柱和带弧表面圆柱轴向电流分布呈圆周对称;锥形圆柱表面电流幅值与其表面曲率半径成正比,锥台形圆柱则正好相反。圆柱形结构表面电流分布规律的研究对具有此类结构的设备的雷电间接效应防护设计具有指导价值。

Lightning indirectly impacts electric equipment or systems through coupling external lightning energy into the interior of shielding enclosures, and induces overcurrent and overvoltage, so internal fields are produced by surface cur- rent penetration. However, rules of the surface currents distribution on cylindrical cavities are far from complete. Hence, using the software CST MICROSTRIPES based on the transmission line matrix method, we calculated the surface current distribution of a finite regular circular cylinder and a finite circular cylinder with curved surface. Four conclusions can be drawn from the simulation on the condition that a lightning current pulse is injected into the circular cylinders： For the regular circular cylinder, the transverse surface current distributes evenly along the axial direction and it is stronger on the front edge and the back edge. For the circular cylinder with curved surface, the transverse surface current descends along the axial direction from the end with the small radius to the other end. Both cylinders have axial surface currents distri- buted with circumferential symmetry. Moreover, for a conical cylinder; the amplitude of surface current is directly proportional to the curvature radius, while for a cone-frustums circular cylinder, the amplitude is inversely proportional to the curvature radius. These conclusions are worthwhile to protecting equipment with structure of circular cylinder against indirect effects of lightning.