论文总字数：31360字

摘 要

高压输电网是现代电力系统的重要组成部分，随着高压直流输电的迅猛发展，输电线路的电压等级不断提高，而处于高场强中的绝缘子在一定条件下会出现破坏性的沿面闪络放电，使得设备的绝缘性能大幅度降低，进而影响到高压设备乃至电网的安全运行。传统解决闪络的方法既费时费力，又无法有效解决问题，近年来，人们相继提出了纳米添加，直接氟化处理，电子束照射，导电涂层等方法，但这些方法由于工艺复杂或易造成环境污染等问题而无法投入应用。现如今，材料表面改性领域兴起的低温等离子技术让人们在提升绝缘材料的绝缘性能方面看到了新的方向。目前使用射流阵列处理绝缘材料以提高其绝缘性能已有相关的研究，但是研究中关注的重点在于改性前后材料物理化学特性的变化，很少关注其电学特性的影响。考虑到我国电力系统发展的需求，需要研究射流阵列改性对绝缘材料表面电学特性的影响。

本课题采用纳秒脉冲电源作为射流单元激励源，以惰性气体Ar作为工作媒质，建立了三管并排的射流阵列改性实验装置和测量系统。通过发光图像和电气特性研究了其放电特性，分析高压电极位置、气体流速以及外施电压对射流阵列放电的影响。最后，在优化后的射流阵列基础上，通过改变电源频率、改性时间和改性距离三个参量，研究射流阵列改性对玻璃的表面电阻、相对介电常数、泄漏电流和沿面耐压的影响。

实验研究表明：在射流阵列中，中间高压电极头部比两侧高出2mm时，三管体羽长度基本保持一致；气体流速为2L/min时，体羽长度达到最大值；在10kV~12kV的范围内，体羽长度随外施电压的增加而略微增长。在改性对玻璃电学特性的影响方面，经射流阵列改性后，表面电阻率最高提升了10倍，相对介电常数略微增长，泄漏电流与外施电压的关系曲线得到了大幅度改善，沿面耐压最高提升了8kV。

关键词：低温等离子体，射流阵列优化，表面电学特性，绝缘材料，改性

ABSTRACT

High-voltage transmission network is an important part of modern power system. With the rapid development of high-voltage direct current transmission, the voltage level of transmission lines is continuously improved, and insulators in high field strength will have destructive flashover under certain conditions. As a result, the insulation performance of the equipment is greatly reduced, which affects the safe operation of high-voltage equipment and even the power grid. The traditional method of solving flashover is time-consuming and laborious, and cannot solve the problem effectively. In recent years, nano-addition, direct fluorination, electron beam irradiation, conductive coatings and other methods have been proposed successively, but these methods can not be applied because of the complex process or environmental pollution. Nowadays, low-temperature plasma technology, which is emerging in the field of material surface modification, has brought people a new direction in improving the insulation performance of insulating materials. At present, there are some related studies on improving the insulation performance of insulating materials by using jet arrays, but the focus of the research is on the changes of physical and chemical properties of materials before and after modification, and little attention is paid to the influence of electrical properties. Considering the demand of power system development in China, it is necessary to study the influence of jet array modification on the surface electrical properties of insulating materials.

In this project, nanosecond pulse power supply is used as the excitation source of the jet unit, and inert gas Ar is used as the working medium. A three-tube parallel jet array modification experimental device and measurement system are established. The discharge characteristics of the jet arrays were studied by means of luminescent images and electrical characteristics. The effects of the location of high voltage electrodes, gas flow rate and applied voltage on the discharge of the jet arrays were analyzed. Finally, on the basis of the optimized jet array, the effects of the modification of the jet array on the surface resistance, relative dielectric constant, leakage current and voltage withstand along the surface of glass were studied by changing three parameters: power frequency, modification time and modification distance.

The experimental results show that in the jet array, when the middle high voltage electrode head is 2 mm higher than the two sides, the plume length of the three tubes keeps basically the same; when the gas flow rate is 2 L/min, the plume length reaches the maximum value; in the range of 10 kV to 12 kV, the plume length increases slightly with the increase of applied voltage. As for the effect of modification on electrical properties of glass, surface resistivity increased by an order of magnitude, relative dielectric constant increased slightly, the relationship between leakage current and applied voltage was greatly improved, and the surface withstand voltage increased by 8 kV.

Key words: Low temperature plasma, jet array optimization, surface electrical properties, insulating materials, modification

目录

第一章 绪论 1

1.1研究背景与意义 1

1.1.1低温等离子体及其产生方式 1

1.1.2等离子体射流及其在材料改性方面的应用 1

1.1.3研究表面改性对绝缘材料表面电学特性影响的意义 2

1.2国内外研究现状 3

1.3本文主要研究内容 5

1.射流阵列放电特性的研究 6

2.射流阵列表面改性对绝缘材料电学特性的影响 6

第二章 实验平台搭建与诊断手段 7

2.1实验平台搭建 7

2.1.1射流阵列结构及实验平台建立 7

2.1.2纳秒脉冲电源简介 7

2.2实验诊断分析方法 8

2.2.1 电气特性诊断 8

2.2.2 光学特性诊断 9

2.2.3 表面电学特性诊断 9

第三章 射流阵列的放电特性 12

3.1 不同高压电极位置变化 12

3.2 不同电压与气流变化 13

3.2.1发光图像 14

3.2.2 电气特性 16

第四章 射流阵列改性玻璃表面 24

4.1 改性材料的选取 24

4.2 表面电阻改性前后对比 24

4.2.1电源频率对改性后玻璃表面电导率的影响 25

4.2.2处理距离对改性后玻璃相对介电常数的影响 25

4.2.3处理时间对改性后玻璃表面电导率的影响 26

4.3 相对介电常数改性前后对比 27

4.3.1电源频率对改性后玻璃相对介电常数的影响 27

4.3.2处理距离对改性后玻璃相对介电常数的影响 28

4.3.3处理时间对改性后玻璃相对介电常数的影响 29

4.4 泄漏电流改性前后对比 29

4.4.1未处理时玻璃泄漏电流与电压的关系曲线 30

4.4.2电源频率对改性后玻璃泄漏电流的影响 30

4.4.3处理距离对改性后玻璃泄漏电流的影响 32

4.4.4处理时间对改性后玻璃泄漏电流的影响 33

4.5 沿面耐压改性前后对比 34

4.5.1不同电极间隙下未处理玻璃的沿面耐压 34

4.5.2电源频率对改性后玻璃沿面耐压的影响 35

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