【作者】 彭军；

【导师】 司马文霞；

【作者基本信息】 重庆大学 ， 电气工程， 2008， 硕士

【摘要】 绝缘子的污秽闪络是对供电可靠性危害极大的区域性事故,被列为电力系统头号安全大敌,防止污闪事故的发生对保证电网安全运行极为重要。虽然污秽引起的绝缘闪络事故在电网总事故中占第二位,仪次于雷害事故,但污闪事故造成的损失却是雷害事故的10倍。国内外虽对绝缘子交、直流污闪特性研究较多,但缺乏对实际输电线路染污绝缘子的耐压特性、闪络特性以及泄漏电流等参数的综合分析,缺乏对运行中的绝缘状态综合评估的研究。本文在总结国内外研究成果的基础上,在输配电装备及系统安全与新技术国家重点实验室(重庆大学)的人工气候室内对220kV输电线路普通型玻璃绝缘子串(FC-100/146)、瓷绝缘子串(XP-70)和复合绝缘子(FXBW—220/110—2150)进行了大量的耐受特性和闪络特性的试验研究,并对耐受和闪络过程中的泄漏电流进行分析。针对不同盐密(ESDD)、灰密(NSDD)和污秽分布不均匀度等对绝缘子串耐受特性和闪络特性的影响,通过试验研究及理论分析得到:绝缘子串的耐受电压和闪络电压随着盐密和灰密的增加下降;耐受和闪络电压随着污秽分布不均匀度的增加而上升,上下表面污秽分布均匀时最低,此时的高湿绝缘子串在运行电压下极易发生闪络;泄漏电流有效均值、最大有效值均随着盐密值的增大而增加,并与盐密值呈幂函数关系。灰密值对泄漏电流的影响规律与盐密一致,但二者对泄漏电流有效值的影响因素在本质上是不同的;根据污闪络电压以及泄漏电流与盐、灰密和不均匀度的关系,得到了满足耐受通过和泄漏电流有效均值不超过40mA这两个条件绝缘子运行发生污闪的威胁程度安全区域图。根据安全区域图和实测污秽度,能够指导确定对运行中绝缘子实施清扫的周期,向状态清扫过渡,提高输电线路运行可靠性。更多还原

【Abstract】 The pollution flashover is the regional accident which has great harm to the power supply reliability and is regarded as the top archenemy to the power system. It is of paramount importance to prevent pollution flashover accidents and ensure the safe operation of the power grid. Insulation flashover, as a result of the pollution, is the second leading cause in contribution to power grid accident, only next to the lightning, but the loss brought by it is as ten times as that by the lightning.There have been many researches on the characteristics of DC/AC pollution flashover of insulator at home and abroad, however the comprehensive analysis of the factors such as withstand voltage, flashover performance and leakage current, as well as the comprehensive evaluation of insulation status of the lines, are still scarce. Under the comprehensive summarization of former domestic and foreign researches, the withstand performance and flashover characteristics of glass insulators (FC-100/146), porcelain insulators (XP-70) and composite insulators (FXBW—220/110—2150) of 220kV lines are tested in the phytotron in The State Key Laboratory of Power Transmission Equipment & System Security and New Technology and the leakage current are analyzed. Based on different impacts of ESDD, NSDD and the uneven distribution of pollution on the withstand and flashover characteristics of insulators, it can be concluded from the testing result and theoretical analysis that: the withstand and flashover voltage of insulators decrease along with the increase of ESDD, NSDD; The withstand and flashover voltage of insulators rise along with the increase of unevenness of the distribution of the pollution and reach a minimum when the distribution is even, while it has a great possibility for the flashover taking place on the wet insulators; The relationship between the max virtual value and ESDD shows a exponential function; The same goes with the impact of NSDD but these two rules are essentially different. According to these relationship, the security region in which the mean virtual value of withstand and leakage currents are both less than 40mA. According to the security region and the practical status of pollution, the cleaning period of insulator and the transition to condition based cleaning can be decided to improve the reliability of transmission lines.更多还原