Power transformer cellulosic insulation destruction assessment using a calculated index composed of CO, CO2, 2-Furfural, and Acetylene.

Power transformer insulation is degraded and decomposed over time. Due to the importance of cellulose, indicators such as 2-Furfural, CO, CO₂, and CO₂/CO ratio are used to investigate cellulose aging status because these are cellulose degradation products. However, various studies have shown that using each of these indicators alone may lead to incorrect cellulose degradation diagnosis. Therefore, a new calculated index called CFA index (an abbreviation of Carbon, Furfural, and Acetylene) that considers the effects of four indicators (CO, CO₂, 2-furfural, acetylene) together will be presented in this paper. The CFA index has been obtained from the analysis of 216 power transformer measurement data using the correlation coefficients calculation. The reason for considering acetylene is the importance of its production and the high correlation coefficient between acetylene and transformer age. In this method, if the transformer has the CFA index between −2 and −5.3, then it can be ensured that the transformer does not suffer from severe cellulose aging or decomposition. The normal range for the CFA index is obtained from investigating data from many power transformers, all with CO₂/CO ratio between 3 and 10. Finally, to verify the accuracy of the CFA index and its ability to detect cellulosic insulation degradation and the inefficiency of other methods in some cases, dissolved gas analysis (DGA) test results of 306 power transformers will be investigated, and results will be fully presented. [ABSTRACT FROM AUTHOR]