基于电路等效变换的绝缘子串电压分布研究

Study on Voltage Distribution along Insulator Strings of EHV/UHV AC Transmission Line Based on Circuit Equivalent Transformation

笔者提出了一种新的基于电路等效变换的绝缘子串电压分布计算方法,不仅具有与电网络法相媲美的普遍适用性,还具有极高的计算效率,易于被各种语言编写成仿真计算程序。通过人工污秽实验确定了绝缘子在各种工况下(良好、劣化、洁净、染污)的基波电容和基波电阻范围,为仿真计算提供了实验依据。运用文中方法和实验数据对某500 kV线路绝缘子串电压分布进行了仿真计算,计算结果和实测一致。对1 000 kV特高压绝缘子串电压分布研究表明,应该在绝缘子串靠近高压导线一侧安装均压环,当安装位置在第3、4片绝缘子之间(即罩入深度为3),均压环与绝缘子串之间的设计杂散电容约13 pF时,均压效果较好。

A new method based on circuit equivalent transformation for calculation of insulator strings is proposed in the paper.This method can be used in every condition which is comparable with the electric-network method.What＇ more,it is much more efficient than other methods,and is easy to be developed into programs by a variety of programming languages.By artificial pollution test,range of the self capacitance and self resistance of the insulator in various conditions（perfect,faulty,clean,polluted） is determined as the input of the simulation program.The simulation result of the voltage distribution along insulator strings of a 500 kV EHV AC transmission line is in line with the actual.Simulation to the voltage distribution along insulator strings of a 1 000 kV UHV AC transmission line shows that corona rings should be installed for a better voltage distribution.The stray capacitance between corona ring and insulators should be about 13 pF to obtain best distribution,which appeared when corona rings were installed at 3-unit-long cover depth.