变电站电磁脉冲耦合倾斜二次电缆数值分析

Numerical Analysis of EMP Coupling to Declining Secondary Cable in Substations

为了研究电磁脉冲耦合二次电缆的机理,基于电磁散射理论建立了脉冲场耦合传输线的三维倾斜时间域有限差分(FDTD)数值分析模型,推导出了三角形网格内的电磁场修正方程,进而计算了电磁脉冲激励下理想导体面上倾斜单导体传输线终端负载上的电流响应。结果表明,随着一端负载逐渐增大另一端负载上电流幅值逐渐减小,但反射逐渐增大。用电磁脉冲模拟器进行的实验验证结果表明,传输线终端负载上电流测量结果与计算结果比较符合,证明建立的三维倾斜FDTD数值模型可用于变电站电磁脉冲耦合二次电缆问题的研究。

Transient electromagnetic interference （EMI） is an important iactor which influences seconaary equipment in substations. In order to investigate the interference mechanism of electromagnetic pulse （EMP） coupling to secondary cable used to make signal transmitting and power transmitting of secondary equipment in substations, a three-dimensional declining finite-difference time-domain （FDTD） numerical model for EMP coupling to transmission line was developed with the electromagnetic scattering theory, and modified equations of magnetic field in triangle grids are achieved by the Maxwells integral equation in the developed numerical model. Current responses on the loads connected to declining single transmission line on perfect metal plane excited by single EMP transmitting through the working region of bounded-wave EMP simulator were computed, the computed results indicate that the current＇s amplitude on the load located at one end of declining transmission line gradually decreases while the load located at the other end of declining transmission line gradually increases, but the amplitude of reflected current gradually increases. EMP coupling to declining single transmission line is experimentally validated by using the boundedwave electromagnetic pulse simulator, the calculated results of the load current connected to declining single transmission line are in good agreement with experimental results, which shows that the developed three-dimensional declining FDTD numerical analysis method is effective to investigate EMP coupling to declining transmission line.