【作者】 王振华；

【导师】 杜伯学；

【作者基本信息】 天津大学 ， 高电压与绝缘技术， 2007， 硕士

【摘要】 我国高原和山地面积占全国总面积的2/3以上,因此,随着西部大开发和国家电网建设的进行,越来越多的复合绝缘子已经在高海拔地区投入运行。由于高海拔地区气压低,环境条件恶劣,这给输电线路外绝缘带来了严重的挑战。复合绝缘子以其优异的耐污闪性能已经得到电力系统的广泛认可和好评,然而在高海拔环境下,其各种优异性能有待于进一步的考察与证实。干燥带放电一直被认为是复合绝缘子老化的主要原因之一,因此,在高海拔环境下对干燥带放电特性的研究就显得特别重要。本文是在人工模拟的不同海拔高度下,通过减压容器分别得到从100kPa到40kPa的七个不同气压,采用2.5mS/cm和5.0mS/cm两种不同电导率的NaCl溶液分别模拟不同的污秽等级,实验试样为硅橡胶绝缘子。在不同的气压和污秽条件下,对硅橡胶复合绝缘子表面干燥带的形成,泄漏电流的特征,干燥带放电的放电特征和频率特征做了对比研究。通过研究得到如下结论:随着气压的降低,硅橡胶复合绝缘子表面干燥带加速形成,然而干燥带的形成区域变小,因此,干燥带放电的累积电量减少;在不同条件下,干燥带放电电流的频率都集中在100-1000 Hz左右,尤以三次谐波(150Hz)左右最多;在常压下,干燥带放电阶段的泄漏电流中导电电流约占70%,干燥带放电电流约占20%,电晕放电电流约占10%,然而在40kPa低气压下,干燥带放电阶段的泄漏电流中导电电流约占75%,干燥带放电电流约占15%,电晕放电电流约占10%;随着污秽等级的发展,表面干燥带加速形成,干燥带放电产生的累积电量增加。更多还原

【Abstract】 The area of plateau and mountainous in our country takes over 2/3, therefore, more and more polymer insulators have been used in high-altitude area along with the Western Development and the construction of state grid. The polymer insulator has received widespread approval and high praise for its outstanding performance, however, the performance under high-altitude environments needs further investigation and confirmation. Dry-band discharge is considered as one of the main reasons which lead to the aging of polymer insulator, so it is necessary to investigate the characteristics of dry-band discharge under high-altitude environmentsIn this paper, an artificial decompression chamber was established to carry out the experiment under the reduced pressures. Seven different atmospheric pressures from 100kPa to 40kPa were obtained to simulate different altitudes. Two kinds of NaCl solutions with the conductance of 2.5mS/cm and 5.0mS/cm were used to simulate different contamination levels. The test sample was a slice of silicone rubber insulator. The contrast researches about the formation of dry band, the characteristics of leakage current, the discharge characteristics and the frequency characteristics of dry-band discharge have been done under different pressures and contaminations.The main conclusions are as follows: With reducing the pressure, the formation of dry band advanced, however the region of dry band diminished, therefore the cumulative charge of dry-band discharge decreased; Under different conditions, the frequency range of dry-band discharge current was almost the same, mostly around 150Hz; Among the leakage current in dry-band discharge stage, conductive current accounts for 70%, dry-band discharge current accounts for 20% and corona discharge current accounts for 10% under the atmospheric pressure; however the conductive current accounts for 75%, the dry-band discharge current accounts for 15% and the corona discharge current accounts for 10% under the low pressure of 40kPa. With the increase of contamination levels, the formation of dry band advanced, and the cumulative charge of dry-band discharge increased.更多还原