气体谱图时频特征在OIP套管状态诊断中的应用

Application of Time-frequency Characteristics of Gas Spectrogram in State Diagnosis of OIP Bushing

为有效利用油中溶解气体分析结果判断油浸纸绝缘套管的缺陷,利用油中溶解气体相对含量构造了气体谱图,提取等效时间长度Teq和等效频带宽度Feq作为气体谱图的特征参量,并用于不同缺陷气体谱图的聚类分离。在此基础上,根据Teq-Feq图形分布结果构造了辨识套管不同缺陷的时频特征值边界,提出了基于谱图时频特征的套管状态诊断方法,并对状态异常的套管进行了诊断。最后,对比分析了谱图时频特征法和Duval三角形法对套管的诊断效果,并利用解体目视检查验证了谱图时频特征用于套管缺陷诊断的有效性。结果表明:采用谱图时频特征能够有效诊断套管状态,其诊断准确率由于Duval三角形法,并且可以弥补Duval三角形法对状态正常套管误判或难以判断的不足,可以作为油浸纸绝缘套管状态诊断的重要依据。

To effectively judge the defects of oil impregnated paper insulation bushing by using the result of dissolved gas analysis,the gas spectrum is constructed by using the relative content of dissolved gases in oil. The equivalent time length Teqand equivalent frequency band width Feqare extracted as the characteristic parameters of gas spectrum,and are used to cluster and separate the gas spectrum of different defects.On this basis,the time-frequency eigenvalue boundary for identifying different defects is constructed,and the state diagnosis method based on the time-frequency characteristics of spectrum is proposed in accordance with the distribution results of the TeqFeqgraph. Finally,the diagnosis effect of time-frequency spectrum method and Duval triangle method is compared and analyzed,and the effectiveness of spectrum time-frequency feature in casing defect diagnosis is verified by visual inspection after disassembly of the bushing.The results show that adopting the time-frequency characteristics of spectrum can effectively diagnose the state of bushing,and its diagnostic accuracy is superior to Duval triangle method and can make up for the defects of Duval triangle method in misjudgment and difficult judgement of normal bushing,which can be used as an important basis for the state diagnosis of oil impregnated paper insulated bushing.