有损土壤上的多导体传输线的时域分析

FDTD analysis of multi conductor transmission lines over lossy ground

:将多导体传输线 (MTL)的土壤复数阻抗拓展为土壤运算阻抗 ,采用 Pade展开法 ,提出了计及土壤影响的多导体传输线的时域模型 ,建立了该模型的时域有限差分 (FDTD)算法。通过对计及土壤影响的架空单导体和双导体传输线的波过程计算 ,表明本文方法的正确性 ,并可以应用于超高压变电站高压母线和超高压输电线路的瞬态电磁干扰计算。

A new time domain model is proposed to deal with the per unit length impedance parameter of multi conductor transmission lines (MTLs) including lossy soil. With the help of Pade's approximation, the model is efficient and accurate, and the coefficients in the model are independent of the MTLs structures and media. And then the finite difference time domain (FDTD) algorithm based on recursive convolution for transient analysis is set up. As examples, the wave processes of overhead single conductor transmission line and double conductor lines with frequency varying parameter due to lossy soil are researched. The comparison with the results based on FFT indicates that the proposed method can give more accurate results and can be used to analyze electromagnetic transient of power transmission lines and buses at power substations.