High Voltage Conduction and Breakdown Phenomena in Dielectrics

电介质中的高压传导和击穿现象

• 批准号: 8913605
• 负责人: Markus Zahn
• 金额: $ 25.02万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-12-15 至 1993-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8913605&HistoricalAwards=false
• 关键词: Voltage; Conduction; Breakdown; Phenomena; Dielectrics

This work attempts to understand conduction, aging, degradation, and breakdown mechanisms in high field stressed gaseous, liquid, and solid dielectrics using new modern optical, electronic, and computer instrumentation to see charge transport effects inside materials that could not be seen before. Insulating dielectrics used in power apparatus, such as transformers and cables, and in pulse power technology, such as Marx generators and pulse forming lines, have their performance affected by injected space charge. The space charge distorts the electric field distribution and introduces the charge migration time between electrodes as an additional time constant over the usual dielectric relaxation and fluid transport times. Charge injection from high voltage stressed electrodes is measured by Kerr electro-optic field and charge mapping measurements. Such optical measurements have been performed for highly purified water, water/ethylene glycol mixtures, transformer oil, silicon oil, liquid and gaseous SF6, liquid nitrogen, and high voltage stressed and electron beam irradiated polymethylmethacrylate. In highly purified water, Kerr electro-optic measurements, voltage-current terminal measurements, and electrical breakdown tests have shown that the magnitude and polarity of injected charge and the electrical breakdown strength depend strongly on electrode material combinations and voltage polarity. Particular tasks are: (1) Kerr effect measurements including low-voltage prestressing of dielectrics; (2) electron beam irradiation of solids; (3) fractal mathematical modeling of electrical breakdown trees; and (4) electrokinetic pumping using traveling wave high voltages.

这项工作试图利用新的现代光学、电子和计算机仪器来了解高场应力气体、液体和固体电介质中的传导、老化、降解和击穿机制，以观察材料内部以前无法看到的电荷传输效应。 用于电力设备（例如变压器和电缆）以及脉冲功率技术（例如 Marx 发生器和脉冲形成线）的绝缘电介质的性能会受到注入空间电荷的影响。 空间电荷扭曲电场分布，并引入电极之间的电荷迁移时间作为通常介电弛豫和流体传输时间的附加时间常数。 通过克尔电光场和电荷映射测量来测量来自高压应力电极的电荷注入。 此类光学测量已针对高纯水、水/乙二醇混合物、变压器油、硅油、液态和气态SF6、液氮以及高压应力和电子束辐照的聚甲基丙烯酸甲酯进行。 在高纯水中，克尔电光测量、电压-电流终端测量和电击穿测试表明，注入电荷的大小和极性以及电击穿强度在很大程度上取决于电极材料组合和电压极性。 具体任务是：（1）克尔效应测量，包括电介质的低压预应力； (2)固体的电子束辐照； (3)电气故障树的分形数学建模； (4)使用行波高压的动电泵浦。