Research Article Interaction of Transformer Oil Parameters on Each Other and on Transformer Health Index Using Curve Estimation Regression Method Morteza Saeid, 1 Hamed Zeinoddini-Meymand , 1 Salah Kamel , 2 and Baseem Khan 3 1 Department of Electrical and Computer Engineering, Graduate University of Advanced Technology, Kerman, Iran 2 Department of Electrical Engineering, Faculty of Engineering, Aswan University, Aswan 81542, Egypt 3 Department of Electrical and Computer Engineering, Hawassa University, Hawassa, Ethiopia Correspondence should be addressed to Hamed Zeinoddini-Meymand; h.zeinoddini@kgut.ac.ir Received 10 November 2021; Revised 24 March 2022; Accepted 8 April 2022; Published 23 April 2022 Academic Editor: Tianqi Hong Copyright © 2022 Morteza Saeid et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Power transformers are one of the most significant and expensive equipment in power systems that are exposed to electrical, thermal, and chemical tensions. e transformer health index is a measure that uses test data and field inspections to assess the condition and determine the remaining life of the transformer. e purpose of this article as a new idea is to determine the relationships between electrical, physical, and chemical parameters of transformer oil, dissolved gases, and the transformer health index. One of the advantages of using the regression method in analyzing transformer data compared to the other methods to evaluate the transformer health index is determining the influence of the parameters that have the most impact on each other. Some achievements of this article are as follows: (1) introducing moisture content as the parameter that plays an effective role in reducing dielectric oil breakdown voltage and improving the transformer health index; (2) determining the inverse relationship between acidity and furfural components; (3) determining furfural as a parameter with the greatest role in reducing the Interfacial tension (IFT) of oil (molecular interconnection); (4) determining CO gas as the parameter with the most role in the production of furfural component; (5) determining C 2 H 2 gas as the parameter with the most role in producing the acid component. For example, with a 1 ppm increase in the moisture component, the oil breakdown voltage decreases by 0.583 kV in the compound, growth, exponential, and logistic regressions, or with a 1 ppm increase in the furfural component, the oil interfacial tension decreases by 0.644 mN/m in power regression. In this article, the curve estimation regression method is used and the results are plotted by SPSS statistical software to analyze the interaction between different transformer parameters. To perform the simulations, test data related to 120 transformers have been considered. 1. Introduction By sampling from transformer oil and performing different tests, many faults in the transformer can be diagnosed, the remaining transformer life can be estimated and the con- dition assessment of the transformer can be specified. e transformer oil decays like most insulation and dielectric materials. is deterioration is due to resistance to electrical stresses and heat transfer from the core and coils to the oil. e condition of the dielectric oil is determined by con- tamination, type of dielectric oil, and the shape of the acid compounds, such as metal sulphide particles. In addition to contamination, dielectric oil decomposes by exposure to partial discharge, arc, and temperature rise. e oil de- composes into low molecular weight gases, oil-soluble gases, and carbon particles. e behaviour of each type of dielectric oil in converting to carbon particles is different. Dielectric oil analysis is the key to detecting the normal and abnormal behaviour of the transformer. e dielectric oil deteriorates due to physical and chemical contamination. Figure 1 shows the stages of the transformer oil and paper insulation failure. ere is always some oxygen in the transformer oil. e presence of oxygen produces CO, CO 2 gases, and acid content. By increasing the temperature in the transformer, Hindawi International Transactions on Electrical Energy Systems Volume 2022, Article ID 7548533, 14 pages https://doi.org/10.1155/2022/7548533