Platform for studying online frequency response analysis of power transformers

Power transformers are among the most critical and valuable assets in an electric utility. Their failure can compromise system security, reliability and result in load shedding. These factors coupled with the long lead times involved in replacement mean that condition based monitoring is fast becoming the norm for minimization of down time. Among the gamut of available test methods, Frequency Response Analysis (FRA) has become a cornerstone method in the appraisal of winding health. FRA is predominantly an offline test, requiring the transformer to be taken out of service, but the move toward a smarter grid continues to drive research into online testing. This paper details the development of a Simulink based toolbox for studying the problems associated with online FRA of power transformers. The toolbox includes various transformer circuit models and proposed online test configurations found in existing literature.