Grey-Extension Method for Incipient Fault Forecasting of Oil-Immersed Power Transformer

In this article, a grey-extension fault forecasting method (GEFFM) based on the grey and extension theories is proposed for oil-immersed power transformers. First, a modified grey model (MGM) is applied to predict the oil-dissolved gas trend of power transformers. Then, a novel extension diagnosis method is presented for fault forecasting according to the gas predicted values of power transformers. The novel fault diagnosis method is based on the matter-element model and extended relation functions. Thus, future faults in power transformers can directly be identified by the degree of correlation. Therefore, the maintenance engineers can switch them safely and improve the reliability of power systems. The application of the proposed method to some power transformers has given promising results.