大型发电机定子槽内振动火花放电机理  

Principles of Vibration Spark Discharge in Stator Slots of Large Generators

作　　者：夏英来[1] 贾志东[1] 张征平[2] 陈海[1] 关志成[1] 王黎明[1] 

机构地区：[1]清华大学深圳研究生院,深圳518055 [2]广东电网公司电力科学研究院,广州510080

出　　处：《高电压技术》2013年第4期1009-1017,共9页High Voltage Engineering

基　　金：国家自然科学基金(50877037)~~

摘　　要：大型发电机定子槽内"振动火花放电"的破坏程度远大于局部放电,因此对该放电的产生原因和所需条件进行了研究。首先应用分布式电容模型及主磁通模型对振动火花放电的机理进行了理论分析,并对线棒槽内中部和端部防晕层表面的感应电压、接地电流进行了理论计算和实验验证,明确了振动火花放电发生的原因;然后搭建了模拟定子槽内振动火花放电的实验平台,通过实验研究了振动火花放电产生所需的感应电压、接地电流的条件,得到了近似为负指数关系的电压电流特性曲线;最后,综合上述理论分析及实验结果,对防晕层电阻率的优化选取进行了计算,得到了能较好抑制定子槽内放电的防晕层电阻率的取值范围,如600MW大型汽轮发电机的防晕层表面电阻率的选取范围建议为7.2～18.9kΩ。The damage brought by vibration spark discharge in high voltage stator slots of large generators is severer than that by partial discharge. Therefore, we studied the cause and necessary conditions of spark vibration spark discharge. Firstly, principles of vibration spark discharge were studied based on a capacitive model and a main magnetic model. Meanwhile, the induction voltage and ground current of the corona layer at the middle and end sections of a bar were calculated and verified through experiments. Thereby, the reason why the vibration spark discharge emerged was clarified. Secondly, a model platform of vibration spark discharge in stator slots was established, by which the induction voltage and the ground current that influenced the emergence of the discharge were studied, namely, the voltage-current（VI） characteristics of the discharge. Finally, the optimal resistivity of corona layer, which could resist the discharge in stator slots, was calculated based on the theoretical analysis and experimental results. For example, for large generators rated at 600 MW, the suggested surface resistivity of corona layer is 7.2-18.9 kΩ.

关 键 词：振动火花放电 防晕层 电容性泄漏电流 主磁通 感应电压 接地电流 电压电流特性 

分 类 号：TM303.3[电气工程—电机]