DGA Analysis of Transformer Oil with Experimental Investigation: An Effective Tool of Condition Monitoring for Power Transformer

Abstract

Dissolved Gas Analysis (DGA) is usually performed for power transformer condition based maintenance activities. The DGA has become a very popular technique for the monitoring the overall health of a power transformer. It is possible to distinguish faults such as partial discharge, over-heating, and arcing in a great variety of oil filled power transformers. A number of samples must be taken over a period of time to discern trends and to determine the severity and progression of incipient faults. Dissolved gas analysis is a certain method to diagnose incipient fault of transformers through the correlation between the content of gases dissolved in transformer oil. The effect of aging on transformer oil physical, chemical and electrical properties was studied using the international testing methods for the evaluation of transformer oil quality. There are many methods used to detect transformer fault, mainly including Rogers Ratio Method, Nomograph Method, IEC method, and Duval- Triangle Method. This paper presented conventional methods for DGA in interpreting the transformer condition during its entire course of operation and a case study for experimental investigation of transformer oil using DGA.

Keywords: Power transformer, faults diagnosis, Duval- Triangle, transformer oil, hydrocarbon gases, partial discharge, dissolved gas analysis