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1、1.2 气体介质的电气强度 1.2 The electrical intensity of gas media,实际工程应用中，击穿电压的确定方式如下： In practical engineering applications, the breakdown voltage is determined as follows:,参照一些典型电极的击穿电压来选择绝缘距离； Reference to some typical electrode breakdown voltages to define the insulating distance; 根据实际电极布置情况，通过实验来确定。 Acco
2、rding to the actual arrangement of the electrode, it can be ascertained through experiments.,空气间隙放电电压的影响因素如下： Practical factors affecting the discharge voltage:,电场情况 Electric field condition 电压形式 Voltage types 大气条件 Atmospheric pressure condition,1.2.1 持续作用电压下的击穿 1.2.1 Continuing voltage breakdown 1.
3、2.2 雷电冲击电压下的击穿 1.2.2 Lightning impulse voltage breakdown 1.2.3 操作冲击电压下空气的绝缘特性 1.2.3 The air insulating characteristics of operating impulse voltage 1.2.4 大气条件对气体击穿的影响 1.2.4 The impacts of atmospheric conditions on the gas breakdown 1.2.5 提高气体击穿电压的措施 1.2.5 Measures to improve the gas breakdown voltag
4、e,本节内容 Contents in this section,实际中，大均匀电场间隙要求电极尺寸做得很大。因此，对于均匀场间隙，通常只有间隙长度不大时的击穿数据，如图1-14所示。 In practice, large-uniform electric field gap required electrode in large size. Thus, for uniform field gap, usually can only obtain the breakdown data when the gap length is not so long, as shown in Figure 1
5、-14.,1.2.1 持续作用电压下的击穿 1.2.1 Continuing voltage breakdown,1、均匀电场中的击穿 Uniform electric field in the breakdown,图1-14均匀电场中空气间隙的击穿电压峰值 随间隙距离d 的变化 Figure 1-14 Various peak breakdown voltage for various air-gap distance in uniform electric field,电极布置对称，无击穿的极性效应； Electrode arranged symmetrically, no polarit
6、y effect; 间隙中各处电场强度相等，击穿所需时间极短； Identical electric field intensity, short breakdown time; 直流击穿电压、工频击穿电压峰值以及50冲击 击穿电压相同； DC breakdown voltage, the peak of power frequency breakdown voltage and 50% impulse breakdown voltage are same; 击穿电压的分散性很小。 Very little dispersion of breakdown voltage.,均匀电场的击穿特性：
7、Uniform electric field breakdown characteristics:,式中 间隙距离，cm；Gap Distance where 空气相对密度。 The relative density of the air,从图 1-14 中可以得出，当 在110cm范围内时，击穿强度 (用电压峰值表示)约等于30kV/cm。 From Figure 1-14, when in the 1 10cm range, breakdown strength (indicated by peak voltage) is about equal to 30kV/cm.,对于图 1-14所
8、示的击穿电压(峰值)实验曲线，可用以下经验公式表示： As shown in Figure 1-14, the breakdown voltage (peak) experimental curve, using the following empirical formula, said:,(1-36),2、稍不均匀电场中的击穿 Slightly non-uniform electric field breakdown,稍不均匀电场的击穿特点： Slightly non-uniform electric field breakdown features:,击穿前无电晕； No pre-brea
9、kdown corona; 无明显的极性效应； No obvious polarity effect; 直流击穿电压、工频击穿电压峰值及50冲击击穿电 压几乎一致。 DC breakdown voltage, peak of power frequency breakdown voltage and 50% impulse breakdown voltage is almost the same.,稍不均匀电场的击穿电压通常可以根据起始场强经验公式进行估算 The breakdown voltage of slightly non-uniform electric field is usual
10、ly based on empirical formula of the initial field strength to estimate,(1-37),(1-38),取决于电极布置，可用静电场计算的方法或电解槽实验的方法求得。 depends on the electrode arrangement and can be obtained by use of electrostatic field calculation method or electrolyzer experimental method.,对于稍不均匀场，当 达临界场强 时， 达到击穿电压 ，从而 For slight
11、ly non-uniform field, when reaches the critical field strength , attains breakdown voltage , and thus,下面给出几种典型的电极结构: Here are some typical electrode structure:,图1-15 几种典型电极结构示意图 Figure 1-15 Schematic diagram of some typical electrode structure 1、同心球 concentric ball 2、球平板 ball - plate 3、球球 ball - bal
12、l 4、同轴圆柱 coaxial cylinder 5、圆柱平板 cylinder - Flat 6、圆柱圆柱 cylinders - cylinder 7、曲面平面 surface - flat 8、曲面曲面surface - surface,球板电极 Ball - plate electrode,(1-42),(1-41),(1-40),(1-39),柱板电极 Column - Plate electrodes,(1-45),(1-46),(1-44),(1-43),平行圆柱电极 Parallel cylindrical electrodes,(1-47),(1-48),(1-49),(1
13、-50),同轴圆柱电极 Coaxial cylindrical electrodes,(1-51),(1-52),(1-53),(1-54),同心球电极 Concentric sphere electrode,(1-55),(1-58),(1-57),(1-56),球球电极 Ball - ball electrode,(1-59),(1-60),(1-61),(1-62),(1-63),另外，对于某些不太好根据经验公式求的电场结构，也可以用 30kV/cm进行大致估算，则间隙击穿电压 为 In addition, for the electric field structure unsuite
14、d to use empirical formula, it can be obtained approximately according to = 30kV/cm, then the gap breakdown voltage is expressed as,3、极不均匀电场中的击穿 Breakdown in very non-uniform electric field,极不均匀场的击穿特性： Very uneven field breakdown characteristics:,电场不均匀程度对击穿电压的影响减弱； Field in-homogeneity has a decline
15、 impact on breakdown voltage; 极间距离对击穿电压的影响增大； Gap length has an increasing impact on breakdown voltage; 在直流电压中，直流击穿电压的极性效应非常明显； In the DC voltage, the polarity effect is very obvious in the breakdown voltage; 工频电压下，击穿都发生在正半周峰值附近。 Frequency voltage, the breakdown always occurs in the vicinity of the
16、peak at plus semi-revolution.,当间隙距离不大时，击穿电压基本上与间隙距离呈线性上升的关系； When the gap distance is not very long, the breakdown voltage is nearly linear increase with the gap-length; 当间隙距离很大时，平均击穿场强明显降低，即击穿电压不再随间隙距离的增大而线性增加，呈现出饱和现象。 When the gap distance is large, the average breakdown field strength significantly lower, which shows the gap breakdown voltage no longer increases linearly with the gap distance
