电力变压器低压绕组变形故障的累积效应分析

本文分析了一起220kV电力变压器低压绕组变形的潜伏性故障,为绕组变形累积效应的理论研究与故障诊断提供了方法和数据支持。首先,在对一台正常运行中的220kV变压器做状态评价时,发现其频率响应分析及短路阻抗试验结果异常,初步判断该变压器低压绕组已变形且抗短路能力下降,及时采取返厂维修措施,消除了变压器存在的潜伏性故障隐患。其次,结合该变压器低压侧断路器的历次跳闸记录及其历次色谱分析、介损试验数据,分析并得出其低压绕组变形主要是由于短路冲击的累积效应造成。最后,根据状态评价结果及故障原因分析,给出了变压器日常运行维护的注意事项及相关建议。

Diagnosis of Cumulative Effect on Deformation Fault of Transformer Lower-voltage Winding

This paper analyzes A latent fault of a 220kV power transformer low-voltage winding deformation is analysed, methods and data support for theoretical research and fault diagnosis of winding deformation cumulative effect are provided in this paper. Firstly, when evaluating the status of a 220kV transformer in normal operation, it was found that the frequency response analysis and the short-circuit impedance test result were abnormal. It was preliminarily judged that the low-voltage winding of the transformer had been deformed and the short-circuit resistance was reduced. Thus the factory maintenance measures were taken in time to eliminate the hidden troubles of the transformer. Secondly, combined with the previous trip records of the low-voltage circuit breaker, the previous chromatographic analysis and dielectric loss test data, it was analyzed and found that the low-voltage winding deformation was mainly caused by the cumulative effect of short-circuit shock. Finally, according to the state evaluation results and the cause analysis of the fault, the precautions and related suggestions for the daily operation and maintenance of the transformer are given.