CARBON MONOXIDE AND CARBON DIOXIDE IN CLOSED-TYPE POWER TRANSFORMERS

Abstract

Gases carbon monoxide (CO) and carbon dioxide (CO2) are formed in transformers in larger quantities as a product of degradation of cellulose, than by oxidation of oil. In transformers with closed-type breathing system, without any indication of failure or fault, it was observed that the concentrations of CO are higher than the typical values according to IEC 60599 and CO2/CO ratios lower than 3 frequently have been found. This paper presents results of laboratory investigation of some influence parameters on formation gases CO and CO2. The typical values for CO as well scheme concerning their ratios need to be revised in standard IEC 60599. The criteria need to be established separately for closed type transformers.