Feasibility of the modulation spectroscopy technique for dissolved gas analysis of insulating oils of high voltage transformers

The deterioration level of high voltage transformer oil components can be inferred by the analysis of specific gases found dissolved in the insulating oil of the transformer. In order to detect very low concentrations, harmonic detection of spectral lines using DFB diode lasers can be employed. In this work the possibility of using this technique to implement a continuous surveillance system for early deterioration detection is investigated A detailed study is described directed to sensor optimization by using C₂H₂ as a model target molecule. The prospects for development of a prototype, optical system for field operation are discussed.