New methodology for diagnosing faults in power transformer windings through the Sweep Frequency Response Analysis (SFRA)

The sweep frequency response analysis (SFRA) is an analysis technique for detecting winding displacement and deformation (among other mechanical and electrical failures) in power and distribution transformers. SFRA as a diagnostic technique must integrate both off-line measurements and interpretation of the data in order to provide an assessment of the condition of the windings. The record interpretation is presently done by experts in the topic, whose criteria could not coincide. Although, there are some proposals for making the interpretation of the data more objective, neither of them integrate human expertise along with the different kinds of parameters obtained from the evaluation of the records in a diagnostic model. This work presents the interpretation of the records by means of an automatic system based on the principles of the fuzzy causal diagnosis, which allows the integration of parameters of different type and the consideration of the knowledge given by experts.