Photo-acoustic spectroscopy for dissolved gas analysis: Benefits and Experience

Dissolved Gas Analysis (DGA) is recognised as a powerful monitoring technique for the detection of developing faults within transformer main tanks and associated oil filled equipment. Extensive historical data, collected by laboratory analysis over the years, allows for accurate result interpretation. Online DGA has become increasingly relevant for timely fault detection, especially in the context of the ageing worldwide transformer fleet. Aspects of laboratory DGA are presented to illustrate the evolution from laboratory analysis to on-line DGA. The benefits of GC are outlined together with an analysis of the difficulties associated with the use of this technology in field based on-line instruments. An introduction to photoacoustic technology is offered, together with examples of benefits associated with using this robust technology in the challenging substation environment. Examples or successful applications of this technology are presented and discussed.