Transformer Diagnosis Approach using Frequency Response Analysis Method

Power transformers are one of the main parts in the electric distribution grid. Electric utilities are really interested in their maintenance because of the critical nature of the failure. Many preventive techniques have been developed to know the state of the transformer, e.g., dissolved gas analysis or tgdelta measurement. Frequency response analysis has been proved as an effective predictive technique and one of the most accurate detecting winding displacements. However, in spite of being a well established and widely used technique, an accurate diagnosis procedure by means of FRA has not been achieved yet. It is possible to know if a fault has occurred but FRA is not able to detect accurately the causes. Our research group has been working in the last years in a model transformer and a diagnosis procedure based on its frequency response. This paper presents the proposed diagnostic procedure and the different steps in which it is divided. Besides, it emphasizes the researches obtained in the diagnosis procedure and shows some experimental results