Condition Assessment of Oil-Impregnated Paper Insulation of Transformers by Using CFA Index and Degree of Polymerization

Nattapong Sornjam  Nattaya Klairuang 

Department of Electrical Engineering. Faculty of Engineering at Sriracha. Kasetsart University Sriracha Campus, Thailand

Abstract

This paper presents a mathematical model of transformer condition assessment index. Using analyze transformer conditions in case of limited data. The CFA index (Carbon, Furfural, and Acetylene) use to assess the degree of polymerization level (DP), which is the value that shows dielectric strength of paper insulation. Both values were obtained by estimating the furan compound (2 furaldehyde, 2FAL) in relation to the technical test results and the transformer capacity. The correlation was determined by a linear regression method. The results shown that the DP value correlated with the CFA index, which obtained from the mathematical model. The coefficient of determination of the power transformer and distribution transformer is 75.63% and 79.66%, respectively. This study used sampling test data from transformer 27 units.