Application of Diagnostic Techniques to Power Transformer – A Case Study

Acoustic Emission (AE) is a nondestructive testing method that has been successfully used in a variety of applications dating back to the early 1970s. It covers the detection of structural-borne sound (in the ultrasonic range) that has been generated by some source of distress. An application has been developed for in-service testing of power transformers to detect, locate and assess both thermal and electrical faults from the sounds originating inside a transformer. DGA is performed on oil-filled transformers all over the world, and the main standards providing guidance for use, analysis, and applications are contained in ANSI/IEEE C57.104 and IEC 60599, commonly known as the "gas guides". The use of DGA as a powerful diagnostic tool is a critical and important aspect of determining the condition and health of a transformer, but it is still not entirely effective as most people tend to use it today.