Fuzzy Logic-Based Incipient Fault Detection in Power Transformers Using IEC Method

Abstract

Power transformers are crucial component of electrical system for reliable and effective electric power transfer. Dissolved gas analysis (DGA) of transformer oil is currently the mostly used method for online diagnostics of power transformers. The International Electrotechnical Commission (IEC) three ratio method, that was established via extensive research on gases created from specific faults, is just one of the interpretive techniques used to diagnose the incipient faults based on DGA results. This technique fails to detect the fault type if the measured ratio of gases are slightly diverged from the crisp boundaries of ranges assigned by this technique. The present paper introduces a fuzzy logic approach to overcome the limitation of the conventional IEC technique. This approach demonstrates a significant improvement in diagnostic accuracy of DGA results. The approach provides more accurate evaluation of transformer problems, thereby assisting power utilities in deciding whether to repair, replace, or refurbish a transformer.