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1、,基本概念：Basic concepts 闪 络: 沿着整个固体绝缘表面发生的放电。 Flashover : gas discharge developing on the entire surface of solid insulation.,1.3 固体绝缘表面的气体沿面放电 1.3 Gas creeping discharge on the surface of solid insulation,在放电距离相同时，沿面闪络电压低于纯气隙的击穿电压。工程中的事故往往由沿面闪络造成，因此有必要研究沿面放电特性。 Flashover voltage follow the solid media
2、 is lower than spatial breakdown voltage of pure gas gap with same anode-cathode distance. Accidents in engineering practice are often caused by a surface flashover, so it is necessary to study the surface discharge characteristics.,高压绝缘子的分类： High-voltage Insulator classification: 按结构分：According to
3、the structures （）绝缘子 Insulator 在机械上起固定，电气上起隔离作用的固体高压绝缘部件。如悬式绝缘子、支柱绝缘子、横担绝缘子等。 Solid medium, such as the suspension-type insulator, post insulator, cross-arm insulator, etc, in the power system plays a mechanical fixation role ，and also as an electric insulation. （）套筒 Insulating sleeve 用作电器内绝缘的容器，如互感
4、器瓷套、避雷器瓷套及断路器瓷套等。 The container used as inside insulation of the electrical equipment, such as porcelain shell for mutual inductor, and also porcelain shell for circuit breaker or lightning arrester, etc.,（）套管 Bushing 用作导电体穿过接地隔板、电器外壳和墙壁的绝缘件，如穿越墙壁的穿墙套管、变压器、电容器的出线套管等。 An insulating lining for an aper
5、ture through which a conductor passes the grounding partition, the housing of electric appliances, and the walls. For instance, the wall bushing, the cable-outlet casing of transformers and capacitors and so on. 按材料分 According to the materials： （1）电工陶瓷 Electrical ceramics （2）钢化玻璃 Toughened glass （3）
6、硅橡胶、乙丙橡胶等有机材料 Silicone rubber, ethylene- propylene rubber and other organic materials,1.3.1 界面电场的分布 1.3.1 Interface electric field distribution 1.3.2 均匀电场中的沿面放电 1.3.2 Creeping discharge in uniform electric field 1.3.3 极不均匀电场中的沿面放电 1.3.3 Creeping discharge in non-uniform electric field 1.3.4 绝缘子的污秽放电
7、 1.3.4 Insulator Contamination Discharge 1.3.5 提高沿面放电电压的措施 1.3.5 Measures of rising creeping discharge voltage,本节内容 Contents in this section,1.3.1 界面电场的分布 1.3.1 Interface electric field distribution,图1-24 介质在电场中的典型布置方式 Figure 1-24 The typical dielectric layout in the electric field （a）均匀电场 （b）界面上电力线
8、有强垂直分量 （c）界面上电力线有弱垂直分量 (a) Uniform electric field (b) Interface electric field with strong vertical component (c) Interface electric field with weak vertical component 1 - 电极 Electrode 2 - 固体介质 Solid medium,界面电场的分布有以下三种典型情况： Three typical situations of interface electric field distribution, shown in
9、 figure 1-24.,(a)固体介质处于均匀电场中，且界面与电力线平行； (a) Solid media in uniform electric field ,of which interface is parallel with electric-field line.,图1-24 介质在电场中的典型布置方式 Figure 1-24 The typical dielectric layout in the electric field （a）均匀电场 （b）界面上电力线有强垂直分量 （c）界面上电力线有弱垂直分量 (a) Uniform electric field (b) Inter
10、face electric field with strong vertical component (c) Interface electric field with weak vertical component 1 - 电极 Electrode 2 - 固体介质 Solid medium,(b)固体介质处于极不均匀电场中，且电力线垂直于界面的分量（垂直分量）比平行于表面的分量要大得多； (b) Solid media in extremely non-uniform electric field , while the vertical component is much larger
11、than tangential component which is parallel with the interface.,图1-24 介质在电场中的典型布置方式 Figure 1-24 The typical dielectric layout in the electric field （a）均匀电场 （b）界面上电力线有强垂直分量 （c）界面上电力线有弱垂直分量 (a) Uniform electric field (b) Interface electric field with strong vertical component (c) Interface electric fi
12、eld with weak vertical component 1 - 电极 Electrode 2 - 固体介质 Solid medium,(c)固体介质处于极不均匀电场中，但在界面大部分地方，电场强度平行于界面的分量要比垂直分量大。 (c) Solid media in the extremely non-uniform electric field, but the component parallel to the interface is greater than the vertical component in most interfacial area.,图1-24 介质在电
13、场中的典型布置方式 Figure 1-24 The typical dielectric layout in the electric field （a）均匀电场 （b）界面上电力线有强垂直分量 （c）界面上电力线有弱垂直分量 (a) Uniform electric field (b) Interface electric field with strong vertical component (c) Interface electric field with weak vertical component 1 - 电极 Electrode 2 - 固体介质 Solid medium,(2
14、) 介质表面的粗糙度 Medium surface roughness (3) 固体介质与电极间的气隙大小 Gap length between dielectric and electrode,图1-25 均匀电场中不同介质的沿面闪络电压 （工频峰值）的比较 Figure 1-25 Different media flashover peak voltage (power frequency) in comparison 1-空气隙击穿air breakdown 2-石蜡paraffin 3-瓷porcelain 4-与电板接触不紧密的瓷 porcelain incompact with t
15、he polar-plate,沿面闪络电压的影响因素： Influences of flashover voltage :,如图125，取决于材料的亲水性或憎水性 As shown in Figure 1-25, depend on the hydrophilicity or hydrophobic nature of the materials.,(1) 固体绝缘材料特性 Solid insulation properties,1.3.2 均匀电场中的沿面放电 1.3.2 Creeping discharge in uniform electric field,其中，前两种因素的影响在高气压
16、时表现得更加明显，如图1-26所示： In which, the former two factors play a much more evident role at high pressure, as shown in Figure 1-26:,图1-26 均匀电场中气压对氮气中沿面闪络电压的影响 Figure 1-26 Affection to Nitrogen flashover voltage for various pressure in uniform electric field 1 - 氮气间隙Nitrogen gap 2 - 塑料plastic 3 - 胶布板textolite 4 - 瓷porcelain,图124(a)为均匀电场中引入一固体介质，沿面闪络电压低于纯空气间隙的击穿电压，主要原因可归结如下： Figure 1-24 (a) shows if a piece of solid media is inserted into a uniform electric field, flashove
