Study Of Fault Diagnosis Of Oil-immersed Transformer Based On Grey Theory

Power transformer is the most important power distribution and transmission equipment.It is also the core equipment of the whole substation and switching station.Therefore,the safe and reliable operation of transformer is an important guarantee of the variable distribution substation and the whole power system's security,high quality,economy and reliable operation.Thus the transformer fault diagnosis is also very important.So it is very important reality and theory significance for fault diagnosis and forecast on it.The analysis of dissolved gas in oil is an important detection method for power transformer in the power sector.When the oil immersed transformer fails,the corresponding characteristic gas will be produced.And the composition and content of dissolved gas in oil can reflect the state and deterioration of mineral insulating oil in power transformer and the actual operation condition of power transformer.So it can find out the latent faults in the transformer in time to diagnose the composition and growth rate of the dissolved gases in power transformer oil.The operation state of power transformer can be predicted through by dissolved gas analysis(DGA).Whether it good or not may count on the forecast result.So appropriate protective measures can be taken to ensure reliable operation of power transformer.At the same time,it is not affected by the external electric field and magnetic field.So this method is an important technique to power equipment realizing the condition based maintenance mode.In this paper,based on the analysis of the principle of the grey system theory and DGA,the fault diagnosis model of oil immersed power transformer with grey correlation model is established.At the same time with the interval estimation,the the interval prediction model of dissolved gas content in oil immersed power transformer is established,The interval prediction model of dissolved gas content in oil immersed power transformer oil in interval estimation,which overcome the problem of predicting only a single value.And the power transformer fault diagnosis software is constructed through by MATLAB,which mainly includes power transformer fault diagnosis based on Grey Relational Analysis,prediction of dissolved gases in power transformer oil based on Grey Theory,power transformer fault diagnosis based on IEC three ratio method.Finally,the diagnosis results are compared with the results of the actual fault,and the fault diagnosis and predict model of power transformer based on grey theory and DGA can better realize fault analysis of power transformer.