This paper presents a new approach to incipient fault diagnosis in power transformers, based on the results of dissolved gas analysis. A set of autoassociative neural networks or autoencoders are trained, so that each becomes tuned with a particular fault mode or no fault condition. The scarce data available forms clusters that are densified using an Information Theoretic Mean Shift algorithm, allowing all real data to be used in the validation process. Then, a parallel model is built where the autoencoders compete with one another when a new input vector is entered and the closest recognition is taken as the diagnosis sought. A remarkable accuracy of 100% is achieved with this architecture, in a validation data set using all real information available. IndexTerms-Transformer fault diagnosis, Dissolved Gas Analysis, autoassociative neural networks, mean shift, information theoretic learning. I. INTRODUCTION his paper describes a new approach to the problem of fault detection and identification in power transformers, that reaches 100% accuracy: a diagnosis system based on a set of autoassociative neural networks. The new model gives indication of no-fault or normal condition of the transformer and, if a faulty condition is detected, it identifies the type of fault. This capacity has not been reached before. Power transformer incipient fault diagnosis based on dissolved gas [1] analysis (DGA) has been attempted many times, due to the economic importance of potential equipment failure. It is a problem prone to be addressed by researchers since the publication an IEC norm (IEC 60599 [2]) and a seminal paper [3] that included a data base for diagnosed failures denoted IEC TC10. A number of models have been proposed, adopting a diversity of techniques: expert systems [4], fuzzy set models [5], multi-layer feedforward artificial neural networks (ANN) [6][7], wavelet networks [8], hybrids fuzzy sets/ANN [9], radial basis function neural networks [10],