Solid-gas interfaces stressed with HV impulses: Surface flashover behaviour and control in the 100s kV regime

高压脉冲下的固气界面：100s kV 范围内的表面闪络行为和控制

• 批准号: 2272904
• 金额: --
• 依托单位: University of Strathclyde
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2272904
• 关键词: Solid; gas; interfaces; stressed; HV

The project will entail characterisation of the flashover behaviour of electrode systems bridged with different solid spacer materials, in air environments. The impulsive voltages applied will have peak magnitudes of up to 300 kV, with a time to half-value of the order of hundreds of nanoseconds. The flashover behaviour of cylindrical samples of three different spacer materials (HDPE, Delrin and Ultem), in air with different levels of relative humidity (<10%, ~50% and >90% RH), and in the pressure range 0.5 to 1.5 bar absolute, will be characterised. Methods to modify the surface finish of samples of the chosen materials, with a view to controlling flashover behaviour in humid environments, will be investigated. Open gaps, of the same inter-electrode gap distance but without a solid spacer, will be tested to provide baseline breakdown data for comparison. The electrode profiles used will give rise to a quasi-uniform field distribution, and the polarity effect under the different sets of test conditions will be quantified.Tests will then be performed in forced airflows, in order to determine the effect on the breakdown characteristics. Contaminants will be introduced into the insulation systems, positioned on the surface of the solid spacers and focussing on triple junctions, and any synergistic effects will be determined. Two different test procedures will be used: a step-up procedure, to determine the peak impulse voltages that initiate flashover under the different sets of test conditions; and overvoltage tests, where the time-to-breakdown of the various insulation systems will be characterised for comparison.Weibull statistical analysis will be performed on the breakdown voltage results generated using the step-up procedure, to separate the performance of the insulation systems by material and surface finish, at different pressures and levels of relative humidity. This will reveal information such as the sensitivity of the different insulation systems to an increase in applied voltage, and threshold levels of applied voltage, below which breakdown of the insulation system is not expected to occur. The time-to-breakdown data generated in overvoltage tests will be subjected to von Laue statistical analysis, allowing estimation of the relative contributions of the mean statistical time and the formative time to the overall time to breakdown under the various sets of test conditions.The experimental data generated throughout the project, and the associated discussion of the mechanisms of discharge initiation and development, will be of interest to designers of high-voltage insulation for pulsed power systems, required to operate reliably in humid conditions, and potentially in the presence of surface contaminants. Recommendations will be made on material selection and the surface finish of solid spacers, tailored for different environmental conditions as appropriate.

该项目将需要表征在空气环境中用不同固体间隔材料桥接的电极系统的闪络行为。所施加的脉冲电压将具有高达300 kV的峰值幅度，具有数百纳秒量级的半值时间。将表征三种不同间隔材料（HDPE、Delrin和Ultem）的圆柱形样品在不同相对湿度（<10%、~50%和>90% RH）的空气中以及在0.5至1.5 bar绝对压力范围内的闪络行为。方法修改所选材料的样品的表面光洁度，以控制在潮湿环境中的闪络行为，将进行调查。将测试具有相同电极间间隙距离但没有实心垫片的开放间隙，以提供基线击穿数据进行比较。所用的电极剖面将产生准均匀的电场分布，并将量化不同试验条件下的极性效应。然后在强制气流中进行试验，以确定对击穿特性的影响。污染物将被引入绝缘系统，定位在固体间隔物的表面上，并集中在三重结上，并将确定任何协同效应。将使用两种不同的试验程序：升压程序，用于确定在不同试验条件下引发闪络的峰值冲击电压;和过电压测试，在这些测试中，将对各种绝缘系统的击穿时间进行表征以进行比较。将对使用升压程序生成的击穿电压结果进行威布尔统计分析，在不同的压力和相对湿度水平下，通过材料和表面光洁度来区分绝缘系统的性能。这将揭示诸如不同绝缘系统对所施加电压的增加的敏感性以及所施加电压的阈值水平之类的信息，低于该阈值水平，绝缘系统的击穿预计不会发生。过电压试验中产生的击穿时间数据将经过冯劳厄统计分析，从而可以估计在各种试验条件下平均统计时间和形成时间对总击穿时间的相对贡献。整个项目中产生的实验数据，以及对放电起始和发展机制的相关讨论，将是感兴趣的脉冲功率系统，需要在潮湿的条件下可靠地运行，并可能在表面污染物的存在下的高电压绝缘的设计者。将针对不同的环境条件，对固体垫片的材料选择和表面光洁度提出建议。