DISSOLVED GAS ANALYSIS (DGA) of Transformer Oil is the most sensitive and reliable maintenance technique, the results of which totally depend on the method of ‘Sampling of Transformer Oil’ and ‘Complete extraction of dissolved fault gases’

TRANSFORMER OIL could be called as ‘Blood’ of transformer since it bathes every internal component of transformer and contains all diagnostic information about faults/ condition of transformer. For achieving accurate DGA results, Transformer oil is sampled, transported and stored in airtight containers without any loss to its gas contents.
     
GAS EXTRACTION is essentially subjecting oil sample to high vacuum of 0.015 mbar and isolating the evolved fault gases. There are three types of gas extractors.
These extractors have been detailed under “ Equipments for Dissolved Gas Analysis of Transformer Oil”

GAS ANALYSIS is done using Gas Chromatograph.  In this microprocessor based instrument, the extracted gases from transformer oil, is injected either manually or automatically. The injected gases pass through different columns and the various gases are detected in PPM (parts per million) level by Thermal Conductivity Detector(TCD), Flame Ionization Detector(FID), and Methanator.