Adsorption semiconductor detector for malfunction diagnosis of high voltage transformers

The basis of the transformer diagnosis is a correlation between a particular malfunction and the content of certain gases dissolved in the transformer oil. A chromatography detector based on a semiconductor sensor was developed to provide for selective and sensitive analysis of H2, CH4, C2H6, C2H4, C2H2, CO—crucial gases for the transformer diagnosis. The semiconductor sensor was based on metal oxides. The sensor sensitivity was increased by doping the sensitive layer with Pt, Pd or their mixtures. The sensor impregnated with 0.84×10−2 M PdCl2 solution satisfied the requirement of simultaneous and sufficient sensitivity to all of the gases. timal conditions of chromatographic separation of the above gases were investigated, and the overall time of analysis was decreased by adding 10-port valves to the chromatography setup. The sensor stability was also investigated, and it was shown that a stable operation of the developed detector can be provided.