发电机出口PT匝间短路故障分析
摘要：某电厂发变组保护A、B柜分别报"定子零序电压高段保护动作"，引起机组跳闸。检查该发电机发变组保护动作、故障录波器均正常，现场发现发电机出口电压互感器（potential transformer，PT）B相5042PT有明显过热。通过分析事故经过，对故障PT完成直阻、绝缘、励磁特性曲线、空载电流测试等试验，确认发电机PT匝间短路是造成此次机组跳闸的主要原因。针对如何提前发现发电机出口PT绝缘裂化故障提出了相应的防范措施，应严格按预试规范要求完成发电机出口PT的局放、3倍频耐压等试验，并对各项常规预试项目数据进行趋势分析，及时发现异常。通过此次发电机出口PT匝间短路故障分析对及时发现设备安全隐患，提高设备运行可靠性起到较好排查作用。定期按规范要求完成相关试验，重视试验数据的趋势分析能有效降低同类型事故发生概率及减小事故范围。
Abstract:Cabinet A and cabinet B of generator protection group of a power plant respectively reported "protection action of stator zero sequence high voltage section", which caused unit trip. It was found that the generator outlet potential transformer(PT) B phase 5042PT was obviously overheated. The accident process, through the breakdown PT finish straight resistance, insulation, excitation characteristic curve, and no-load current test, PT interturn short circuit are the main reasons of the unit tripping. In view of how to find early export PT insulation fault, the corresponding measures to prevent cracking was proposed. Specification requirements must be strictly according to the forecast to complete generator export PT partial discharge, triple frequency withstand voltage test, etc. In addition, the trend analysis was carried out on the data of various routine pre-test projects to detect the abnormality timely. The analysis of PT turn-to-turn short circuit fault at the generator outlet plays a good role in finding out the safety hidden danger and improving the reliability of the equipment. The regular completion of relevant tests in accordance with the standard requirements and the emphasis on the trend analysis of test data can effectively reduce the occurrence probability of the same type of accidents and reduce the scope of accidents.
标题：发电机出口PT匝间短路故障分析
title:Analysis of PT Interturn Short Circuit Fault in a Generator Outlet
作者：刘惠娟,王颖明,苏力
authors:Huijuan LIU,Yingming WANG,Li SU
关键词：发电机出口PT,匝间短路,零序电压,
keywords:generator outlet PT,interturn short circuit,zero sequence voltage,
发表日期：2018-10-30
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