Transformer Oil DGA Monitoring Technology

As use of dissolved gas analysis (DGA) monitors increases as a growing component of transformer maintenance and reliability, it is imperative to understand the capabilities of monitors in their ability to align with conventional laboratory results and detect gas-related changes from a baseline. SDMyers studied DGA monitors from several manufacturers through experiments over 18 months. Technologies included in the study were gas chromatography, photo-acoustic spectroscopy, solid-state palladium, thermal conductivity detection, and selective membrane methods. This paper summarizes conclusions from that study based on technology employed.

Introduction
Transformer monitoring is a rapidly growing field. It is estimated that the market for DGA monitors will increase from $113 million in 2012 to more than $755 million in 2020 [1]. This includes expansion from predominantly utility and generation monitoring into wider and broader application throughout the power grid and into industrial application as well. It is increasingly common to purchase DGA monitors at time of purchase of new transformers, and adding monitors to critical in-service transformers is becoming a significant component of transformer maintenance and reliability programs. 

DGA monitor manufacturers use many different technologies for the purpose of dissolved gas detection in active monitoring. The major manufacturers predominantly use gas chromatography (GC), photo-acoustic spectroscopy (PAS), solid state (SS), thermal conductivity detector (TCD), or selective membrane (SM) based sensors. These technologies have been in active use for several years, though GC is currently the only gas detection method referenced in IEEE standards for gases generated in oil-immersed transformers [2]. Other emerging DGA monitoring technologies not included in this study...  

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