一台220 kV主变在绕组故障分析与处理过程中引发的思考

Analysis and Treatment of a 220 kV Main Transformer Winding Fault

介绍了一起220 k V主变跳闸故障发生后运用油色谱分析、电气试验和绕组变形诊断等试验手段快速查找故障点的位置及其返厂处理过程。通过对该起事故的原因进行深刻分析,总结得出变压器绕组抗短路电流冲击能力的大小不仅与主变的设计、制造工艺、所选用材质有关,还与设备的运行管理维护有极大的关系。鉴于此,优化变压器的设计选型、改善运行条件、尤其对遭受多次短路电流的冲击但运行中无异常情况的大型变压器也应根据所遭受短路冲击累积次数和短路电流的大小来决定是否需要停电进行绕组变形诊断,必要时开展专家论证,根据绕组变形程度的轻重来决定绕组是否需要检修或更换,防止大型变压器带病运行。

This paper introduces the rapid fault locating process of a 220 kV main transformer when a tripping accident occurred, which utilized the oil chromatographic analysis, electrical test and winding deformation diagnosis. Besides, the processing procedure in the factory is also included. Through the in-depth accident analysis, it is found that the ability of the transformer winding to resist the impact of short-circuit current is not only related to the design, manufacturing technique and material selection of the transformer, but also depends on the operation and management. Therefore, it is necessary to optimize the design and type-slection of transformer and improve the operating conditions. Particularly, the necessity of a power outage for winding deformation diagnosis should be determined according to the impact of cumulative frequency and the level of the short-circuit current of the large transformer, which has suffered the impact of short circuit current several times, but has no abnormal operations. The expert argumentation should be carried out when necessary. The necessity of repairing or replacement should be determined according to the degree of winding deformation to prevent the large transformer to operate with trouble.