500kV变压器绕组股间短路特征分析  

Analysis of Strand-to-strand Short-circuit Fault in 500kV Transformer

作　　者：甘强 房欣欣 张鹏飞 章思远 GAN Qiang;FANG Xinxin;ZHANG Pengfei;ZHANG Siyuan(State Grid Jiangsu UHV Company,Nanjing 211100,China)

机构地区：[1]国网江苏超高压公司,江苏南京211100

出　　处：《变压器》2024年第2期63-68,共6页Transformer

摘　　要：股间短路是变压器较难查找的缺陷之一。本文中作者介绍了一起500kV变压器股间短路的案例,分析了存在股间短路的变压器在运行、试验、解体阶段所呈现的特征,为此类缺陷的甄别提供案例参考。指出股间短路变压器色谱异常增长与负荷相关;直流电阻、电压比等试验无法发现股间短路缺陷,股间短路点过热将导致局部绝缘劣化,试验上可能表征为局部放电异常、介损增大等;变压器返厂后通过股间绝缘试验验证了缺陷性质,采用电阻测量准确锁定了缺陷部位;采用Ansoft软件对变压器开展电磁计算,发现短路点的能量密度与短路点的电阻有直接关系,为色谱阶跃式增长的现象提供了支撑。Strand-to-strand short-circuit fault is a dificult defects to find in transformers.This article introduces a case of a 5ookV transformer strand-to-strand short-circuit fault.It analyzes the characteristics of the faulty transformer during operation,testing,and disassembly stages,which provides a case reference for identifying such defects.It is pointed out that the abnormal chromatographic growth of short-circuit transformer between strands is related to load.The DC resistance,voltage ratio and other tests carried out on site failed to define the strand-to-strand short-circuit fault.Overheating of short circuit points between strands will lead to local insulation deterioration,which may be characterized by abnormal partial discharge and increased dielectric loss in tests.When the transformer returned to the factory,the defect properties were verified through inter strand insulation tests,and the defect point was accurately located through resistance measurement.Electromagnetic calculations for transformers is conducted by Ansoft software.It is found that the energy density of the short-circuit point is directly related to the resistance of the short-circuit point,providing the support for the phenomenon of chromatographic step growth.

关 键 词：变压器 色谱异常 故障特征 

分 类 号：TM406[电气工程—电器]