Research of pre-warning and diagnosis for transformer based on on-line monitoring devices

The real-time pre-warning and fault diagnosis for transformer based on on-line monitoring devices is proposed in this paper. The values and growth rates of online monitoring variables, together with the information about ex-factory and hand-over tests and monitoring values and variables of similar equipment of the same substation, can be used to make accurate and in-time pre-warning for the transformer that may have default. The possible reason to the abnormal individual parameter was analyzed based on the fault diagnosis of the online monitoring variables. Comprehensive analysis was made on the oil chromatogram with improved three-ratio method, Duval´s triangle method and pictorial method. Then the reason to the transformer fault was diagnosed with the expert system integrated with multiple parameters to acquire detailed information, handling measure and relevant example of the fault. Finally, the feasibility and efficiency of the method proposed in this paper is demonstrated by the experiment.