Colorimetric methodology for monitoring the cellulose insulating paper degradation in electrical equipments filled with mineral oil

摘要

During the operation of electrical equipments the compound 2-furfuraldehyde (2-FAL) and other related furanic substances are produced from the insulating paper degradation and can be detected in the mineral oil by high performance liquid chromatography (HPLC). Their concentration increase can be used to estimate the quality of the paper insulation inside the equipments. In this work colorimetric methodologies for quantification of these furanic degradation products in oil filled electrical equipment were evaluated. Two analytical methods were studied using aniline and modified Winkler’s reactions. For this purpose used oil samples and 2-FAL standard oil solutions were analyzed and the results for both methods were compared with HPLC analysis. The obtained results for 2-FAL standard oil solutions were in accordance with both methodologies. The results obtained for used mineral oil showed that the analysis of furanic compounds by the colorimetric methods may induce to false positive results due to the interference of oil oxidation by-products in the quantitative analysis.