700MW水轮发电机中性点CT故障原因分析及其改进方法  

Analysis and Treatment of a Neutral Point Current Transformer Fault in 700 MW Hydro-turbine Generator

作　　者：何强 杨烽[1] 钟健青 饶蕾 HE Qiang;YANG Feng;ZHONG Jianqing;RAO Lei(Three Gorges Hydropower Plant,China Yangtze Power Co.,Ltd.,Yichang 443133,China)

机构地区：[1]中国长江电力股份有限公司三峡水力发电厂,湖北宜昌443133

出　　处：《水电与新能源》2021年第2期50-53,共4页Hydropower and New Energy

摘　　要：针对一起700MW水轮发电机中性点CT故障,通过对CT进行检查、试验、解体,判断故障原因为该CT二次绕组匝间短路。经研究采用一种增强型CT,通过增加屏蔽绕组的导线截面,降低电流密度,提高CT本身屏蔽能力,将屏蔽绕组绕制方式由内侧调整至二次绕组外侧,不仅降低了CT的温升,也便于人员对CT进行温度监测,确保了机组安全稳定运行。A neutral point current transformer fault in 700 MW hydro-turbine generator is analyzed.Through the inspection,testing and disassembly of the current transformer,it is found that the fault is caused by the inter-turn short circuit of the secondary windings.Then,an enhanced current transformer is adopted to ensure the safe and stable operation of the unit,in which the cross section of the shielding winding is increased to reduce the current density and improve the self shielding capacity of the current transformer,and the shielding winding is adjusted from the inner side to the outer side of the secondary winding to reduce the temperature rising and facilitate the temperature monitoring of the current transformer.

关 键 词：700 MW水轮发电机 匝间短路 解体 屏蔽绕组 增强型CT 

分 类 号：TM312[电气工程—电机]