摘 要

随着当前国家对能源体系的改革，我国的能源行业开始朝着安全、绿色、经济、可靠的方向不断发展，从而使气体绝缘输电线路也获得了极大的发展，它在特高压、核能发电等工程中起着相当重要的地位。

为此，论文以目前被广泛使用的550kV额定电压，4000A额定电流的GIL设备为研究对象，分析它在电磁场、热场以及流场下的内部运行情况，搭建了GIL多物理场耦合计算仿真模型，讨论了GIL尺寸、环境温度对设备绝缘裕度的影响，在此基础上得到了内部绝缘性能最佳的GIL尺寸参数。论文的主要工作有：

1. 将多物理拆分为单个的物理场，以此分析GIL在各个物理场下的数学控制方程和边界条件，并且得到四个物理场的耦合关系；从理论上对绝缘裕度进行定义，并且得出绝缘裕度的计算流程。
2. 使用多物理场耦合场仿真软件COMSOL对GIL进行建模仿真计算；依次对单电场、单磁场进行仿真计算，最后再通过之前得到的场与场之间的耦合关系进行多场耦合仿真，并且对仿真结果进行分析。
3. 依据之前得出的模型，对GIL尺寸以及环境温度对绝缘裕度的影响进行分析研究；首先分析出绝缘裕度的实用计算表达式，再通过软件对各种情况下的绝缘裕度进行计算以及数据拟合，得出最佳内绝缘性能的GIL尺寸参数。

论文的研究表明：GIL内部电场与其他物理场可以看做相互独立，互不影响，而磁场、热场和流场存在着双向耦合的关系；本文采用的550kV，4000A的GIL设备在正常工作环境下拥有良好的绝缘裕度；并且GIL的导体厚度、导体位置、内径大小都会对设备的绝缘裕度造成不同程度的影响，但相比之下外部环境温度对绝缘裕度的影响就要小得多。

关键词：GIL；SF₆临界击穿场强；COMSOL；多物理场耦合；尺寸优化

Abstract

With the current national reform of the energy system, China's energy industry has begun to develop in the direction of safety, green, economy and reliability, thus making the gas insulated transmission lines have also achieved great development, which plays a very important role in high voltage, nuclear power generation and other projects.

This paper, at the current widely used 550 kV rated voltage, rated current 4000A GIL equipment as the research object, analyze it in electromagnetic field, thermal field and the internal operation of the flow field, set the GIL more physical field coupling calculation simulation model of GIL size is discussed, the influence of environment temperature on equipment insulation margin, on this basis to get the best GIL size parameters of the internal insulation performance. The main work of the paper is as follows：

1. Split the multiple physics into a single physical field, so as to analyze the mathematical governing equations and boundary conditions of GIL in each physical field, and obtain the coupling relationship of four physical fields; The insulation margin is defined theoretically and the calculation flow of insulation margin is obtained.
2. The multi-physics field coupling field simulation software COMSOL was used for modeling and simulation calculation of GIL; The single electric field and single magnetic field are simulated successively. Finally, the coupling relationship between fields obtained before is used to conduct multi-field coupling simulation, and the simulation results are analyzed.
3. According to the previous model, analyze and study the influence of GIL size and ambient temperature on insulation margin; First, the practical calculation expression of insulation margin was analyzed. Then, the calculation and data fitting of insulation margin in various situations were carried out by software, and the GIL dimensional parameters of optimal internal insulation performance were obtained.

The research of the paper shows that the electric field in GIL can be regarded as independent from other physical fields, while the magnetic field, heat field and flow field have a two-way coupling relationship. The 550kV, 4000A GIL device used in this paper has a good insulation margin in normal working environment. Besides, the conductor thickness, conductor position and inner diameter of GIL will affect the insulation margin of the equipment to different degrees, but the external environment temperature has much less influence on the insulation margin.

Key Words：GIL；Critical electric field of SF₆；COMSOL；Multiphysics；Size optimization

目 录

摘 要 I

Abstract II

第1章 绪论 1

1.1 课题研究背景及意义 1

1.2 国内外研究现状 2

1.3 本文结构及主要内容 3

第2章 GIL多物理场耦合的模型研究 4

2.1 GIL绝缘裕度的表征及其理论计算方法 4

2.2 GIL设备的电场数学模型 6

2.3 GIL设备的磁场数学模型 6

2.4 GIL设备的热场数学模型 7

2.5 GIL设备的流场数学模型 9

2.6 电、磁、热、流多物理场的耦合 10

第3章 550kV GIL耦合场的仿真结果及分析 11

3.1 GIL电场的仿真计算 11

3.2 GIL磁场的仿真计算 14

3.3 GIL磁场、热场、流场的耦合建模仿真 17

第4章 基于绝缘裕度的GIL尺寸优化 21

4.1 绝缘裕度的计算 21

4.2 导体位置对绝缘裕度的影响 22

4.3 导体内径对绝缘裕度的影响 24

4.4 导体厚度对绝缘裕度的影响 25

4.5 外界环境温度对绝缘裕度的影响 26

4.6 GIL尺寸的优化 26

第5章 总结与展望 28

参考文献 29

致 谢 31

第1章 绪论

气体绝缘输电线路即GIL（Gas insulated transmission line），作为当前架空线路输电的有效替代方案，其具有可靠性更高、对空间的要求更小、电磁辐射更小等优点；现在人们越来越关注气体绝缘输电技术，从而去研究GIL在实际工作环境下的运行情况以及它的绝缘裕度便是本文着重去研究的问题。

1.1 课题研究背景及意义

我国的能源体系正处于改革之中，国内的电力行业也正在朝着更加安全，更加高效，更加环保的方向进发，也正是在此背景之下，气体绝缘输电线路获得了越来越多的学者的关注。GIL是在GIS的基础上发展出来的技术，而GIS（Gas insulated switchgear）的中文全称是气体绝缘封闭组合电器，更加具体的说，其是由断路器、隔离开关、检修接地开关、负荷开关、电流互感器、电压互感器、避雷器、母线等众元器件组合而成的，并且在之中充入一定压力的SF₆气体，充入的SF₆气体的作用是作为灭弧的绝缘介质。如图1.1所示为在各种情况下GIL设备的应用。

图1.1 GIL的应用