巨型水轮发电机组中性点接地装置参数配置研究  

Study on parameters configuration for neutral grounding equipment of giant generator

作　　者：刘亚青 朱钊 张丹丹[2] LIU Yaqing;ZHU Zhao;ZHANG Dandan(Changjiang Survey, Planning, Design and Research Co., Ltd,Wuhan 430010, China;State Key Laboratory of Advanced Electromagnetic Engineering and Technology,Huazhong University of Science And Technology, Wuhan 430074, China)

机构地区：[1]长江勘测规划设计研究有限责任公司,湖北武汉430010 [2]华中科技大学强电磁工程与新技术国家重点实验室,湖北武汉430074

出　　处：《人民长江》2019年第6期143-147,共5页Yangtze River

基　　金：长江勘测规划设计研究有限责任公司自主创新课题项目“巨型水轮发电机引出线工程关键技术研究”(CX2015Z31)

摘　　要：乌东德和白鹤滩水电站单机装机容量分别为850 MW和1 000 MW,发电机容量和电压等级均超出了既往工程。发电机中性点接地装置作为发电机重要的辅助设备之一,其参数的配置是根据发电机定子回路对地电容来确定的。巨型水轮发电机组定子回路对地电容非常大,其中性点的接地装置参数若继续采用传统的高阻接地方式进行配置,将无法满足目前标准所推荐的安全接地故障电流限值。为此,对巨型水轮发电机组中性点接地装置参数配置专门进行了探讨研究。首先针对铁芯烧蚀提出了故障电流限值;然后,基于暂态过电压及接地故障电流限值,提出了加补偿电抗的接地方式;最后提出了采用补偿电抗接地方式下的中性点位移电压计算公式。研究表明,巨型水轮发电机组中性点接地装置参数的配置,需对故障电流、暂态过电压及中性点的位移电压进行综合考虑。The unit capacity of generators applied in Wudongde Hydropower Station and Baihetan Hydropower Station are 850MW and 1000MW respectively, whose unit capacity and voltage level of generators exceed the engineering experience. Generator neutral grounding equipment is one of the most important auxiliary equipment. Parameters configuration is determined by phase to ground capacitance of generator stator circuit. If adopting traditional high resistance grounding, as the phase to ground capacitance of generator stator circuit for giant generator is so high that grounding fault current of generator can not meet the limiting value proposed by standards. To this end, a study is carried out. Firstly, the fault current limiting value of iron core ablation is proposed;then compensating reactance grounding method is proposed based on transient overvoltage and grounding fault current;at last, the neutral shift voltage calculation method for compensating reactance grounding method is proposed. The giant generator neutral grounding method should be determined according to grounding fault current, transient overvoltage and neutral shift voltage.

关 键 词：中性点接地装置 故障电流 暂态过电压 中性点位移电压 巨型水轮发电机组 

分 类 号：TV734[水利工程—水利水电工程]