Dissolved Gas Analysis - Past, Present and Future

It has been well over thirty years since dissolved gas analysis, DGA, was introduced as a diagnostic tool for monitoring mineral oil filled transformers. It is now universally accepted as the method of choice to locate incipient thermal and electrical faults. DGA methodology and applicability have evolved significantly since its inception. The evolutionary development includes new laboratory methods, on-line DGA, application to additional types of fluid filled equipment, application to dielectric fluids other than mineral oil and new diagnostic interpretation protocols. At this time the ASTM has approved two procedures for laboratory DGA and a third method is on the verge of approval. Devices, which periodically or continuously monitor one or more gas in oil concentrations, are available for on-line analysis. DGA was originally developed for transformers, but it is now being applied to load tap changers, oil filled circuit breakers, oil filled bushings and cable oil. Data interpretation methods have been extensively developed for transformers filled with mineral oil and IEEE is currently developing a guide for silicone fluid filled transformers.