Catastrophic failure prognosis of oil-Immersed high voltage transformers

Abstract

Power transformers are important to electric power systems and valuable to utilities. Electrical faults within transformers leading to catastrophic failures or explosion may be substantial both in safety and financial terms. Dissolved and free gas analysis (DGA) is one of the most widely used diagnostic tools for detecting and evaluating faults in electrical equipment, but standard interpretation of DGA is often complex and with ambiguous parameter criteria. This paper describes an effective innovation – chromatic interpretation of DGA. By using chromatic processing techniques on DGA data it is able to identify trends to failure at an early stage via the locus of points on a chromatic map and classify fault patterns via the layout of points based on the results of 50 high voltage transformers. A concept of probability of failure is also suggested, based on the chromatic interpretations.