Studying the loss of life of natural-ester-filled transformer insulation: impact of moisture on the aging rate of paper

Abstract

Studying the loss of life of ester-filled transformer insulation:Impact of the moisture content on the ageing rate.

Study on the Effects of Thermal Aging on Insulating Paper for High Voltage Transformer Composite with Natural Ester from Palm Oil Using Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive X-ray Spectroscopy (EDS)

“…Figure 8a,b show that the intensity of the peak absorbances of the C-H functional groups of transformer insulation paper have increased with aging due to hydrolysis of the natural ester and transesterification of the transformer insulation paper. as shown in Figure 8 [10]. So, the long alkyl chain which is initially part of fatty acids in natural ester binds to cellulose.…”

“…Natural ester molecules are triglycerides, which consist of three fatty acids and one glycerol molecule [9]. Triglyceride and three water molecules are involved in hydrolysis reaction [10,31]. Figure 6 shows the hydrolysis reaction of natural ester [10].…”

“…Triglyceride and three water molecules are involved in hydrolysis reaction [10,31]. Figure 6 shows the hydrolysis reaction of natural ester [10]. This process generates glycerol and long chain of fatty acids and then the long chain fatty acids which have long-alkyl-chains (-R) consisting of a lot of C-H functional groups bind to the cellulose through transesterification generating transesterified cellulose and three molecules of water as shown in Figure 7.…”

Fourier Transform Infrared (FTIR) Spectroscopy Analysis of Transformer Paper in Mineral Oil-Paper Composite Insulation under Accelerated Thermal Aging

“…An alcohol is transformed into ketone by an oxidation process. In this process, the hydrogen of the O-H group is displaced toward the carbon group and the CH 2 OH groups react with oxygen linking the glucose molecules, thereby cleaving the chain as shown in Figure 5 [29,30]. This intensity of peak absorbance located close to 3329 cm −1 can be associated with a reduction in molecular weight or the DP value [7].…”

“…The intensity of these absorbance peaks at 2922 cm −1 and 2854 cm −1 increase with aging due to the adsorption process of the mineral oil to the paper surface during aging [7]. The major degradation of the aging mechanism in mineral oil is oxidation [7,29]. Oxidation decomposes the hydrocarbon molecules into other substances: hydroperoxide, alcohol, aldehyde, ketones, and esters.…”