导　　师： 陈世元;黄松波

学科专业： 080801

授予学位： 硕士

作　　者： ;

机构地区： 华南理工大学

摘　　要： 变电站内的电容器故障频繁发生,甚至发生严重的电容器破裂、外熔丝群爆等事故,直接经济损失较大,对电网安全运行构成很大威胁,也威胁到运行维护人员的人身安全,研究电容器的损坏原因具有非常重要的应用价值和学术意义。作者在总结国内外现有研究成果的基础上,对吉安变电站的电容器进行了分析和研究。 本文的主要研究工作是：首先,对电容器投切时出现的操作过电压、电容器投入运行时产生的合闸涌流、电网谐波产生过电压、开关频繁操作对电容器损坏的累积效应、运行环境的温度对电容器寿命的影响进行了分析；接着,运用EMTP仿真软件重点对电容器受操作过电压和电网谐波的影响做了仿真分析；最后,运用并联电容器在线监测系统对电容器的运行电流、谐波情况和三相电压波形进行监测,实时查看电容器组各电容器上的运行电压、电流、谐波分布情况,实时监控电容器的状态参数记录分合闸以及电容器发生故障时的电流、电压、谐波参数和波形,通过分析监测系统记录的故障数据和波形准确判断出故障的主要原因。 通过试验研究和理论分析,本文得出的主要结论如下：电容器的损坏主要受电容器极间电场强度和内部高温的影响,长时间在高温运行环境下,电容器绝缘介质的损耗增大、温度升高导致绝缘进一步老化,击穿电压降低,在有过电压的情况下,电容器内部的薄弱元件会首先击穿,从而造成电容器的损坏。 In recent years, individual transformer substation's capacitors break down frequently. The Phenomenon of capacitor bursting and fuse exploding appears. the accident cause economic lose and threat to the electrical network and the running person. This paper mainly carried out the studies as follows. firstly, this paper analysizes the influence on the life of capacitor by the following factors as the over-voltage when the capacitor switches on//off,inrush current when the capacitor switches on, over-voltage due to the harmonics, ambient temperature and so on. secondly using the EMPT simulation software analysizes the influence on capacitor by the switching over-voltage and the harmonics. Thirdly,the current, harmonics and voltage is monitored and measured in time by online monitoring system on shunt capacitor. the current, harmonics and voltage can be instantly retrieved. And the state parameter of the capacitor and the data and waveform when it is fault is monitored in time. The major fault cause is accurately obtained by analysizing the fault data and waveform monitored and measured by the online-monitoring system. The findings indicate that capacitor fault is due to high electric-field intensity and the overheated influence. If the capacitor operate in the hot environment and in the overvoltage situation for a long time, the capacitor interior weak part will penetrate, which caused capacitor's breakdown.

关 键 词： 电容器故障 在线监测 过电压 击穿

分 类 号： [TM53]

领　　域： [电气工程]