基于无源滤波器设计理论的半波长输电线路调谐电路特性分析

Discussion on Characteristics of Compensation Circuits for Tuned Half-wavelength Transmission Lines Based on Filter Design

调谐电路是特高压半波长线路能够灵活应用于不同传输距离的关键技术。该文通过分析传统调谐电路的结构特点,根据模拟滤波器设计理论,得出调谐电路本质为无源低通滤波器这一重要结论,而传统调谐电路结构完全等同于定k型低通滤波器,会在截止频率附近产生增益与时延的放大。选取Bessel滤波器进行调谐电路参数设计,通过仿真计算比较自然半波长线路、传统调谐半波长线路与Bessel型调谐半波长线路在不同运行状态下的沿线电压幅值分布,发现Bessel型调谐半波长线路能够获得与传统调谐半波长基本一致的沿线电压分布特点。而在发生雷击、故障等暂态过程时,Bessel型调谐电路能够抑制高频冲击在传统调谐电路中产生的高频振荡,其性能优于传统调谐电路。

The compensation circuit is the cardinal technology for the flexible application of half-wavelength transmission lines(HWTL).Indeed,the structure of compensation circuit is equivalent to that of the passive analog filter.Therefore,the compensation circuit can be designed based on parameters of passive analog filters without requiring of identical parameters of each passive device as previous studies.This paper proposed a parameter design method of compensation circuit based on Bessel filter,which was able to reduce harmonics of electromagnetic transients of traditional compensation circuits.In consideration of requirements of compensation circuits,Bessel filter was selected based on the analysis of frequency responses and times delays of different passive analog filters.Based on comprehensive simulations,it can be concluded that the compensation circuit designed by Bessel filter is quite similar to natural HWTL with voltage distribution in different cases.However,faults or operations cannot induce oscillations in Bessel based compensation circuits.