Diffusion coefficient in transformer pressboard insulation part 2: mineral oil impregnated

Multi‐physics modelling approach for investigation of moisture dynamics in power transformers

“…By using dielectrometric sensors and mathematical tools to solve Fick's equation, Du et al [4, 13] calculated the diffusion coefficient for non‐impregnated pressboard. Over the past several years, Garcia et al [14–16] reported a series of diffusion coefficients, where the thickness of the oil‐impregnated pressboard was taken into consideration.…”

Particle tracing modelling on moisture dynamics of oil‐impregnated transformer

“…By using dielectrometric sensors, Du [7] studied the diffusion coefficients for non-impregnated pressboard. Recently, a series of diffusion coefficients considering pressboard thickness was reported by García [8,9].…”

“…Table 3 compares the calculated average moisture concentration of the pressboard based on Fick's law and particle tracing method. Since moisture diffusion coefficients have a significant influence on the moisture distribution, a comparison of the moisture distribution for oil-impregnated pressboard by using Foss, Guidi [2] and García's diffusion coefficients [8] is provided in Table 3.…”

“…Many researchers studied moisture diffusion using Fick's diffusion law and determined diffusion coefficients by conducting experiments on pressboard samples [2][3][4][5][6][7][8][9]. Instead of adopting Fick's diffusion law, this paper proposes a novel particle tracing method to estimate moisture of oil-impregnated cellulose in transformers.…”

A New Method for Evaluating Moisture Content and Aging Degree of Transformer Oil-Paper Insulation Based on Frequency Domain Spectroscopy

“…Blennow [19] studied measurement of moisture content in field transformer based on field experience, and presented that precautions should be taken with the results to minimize effects caused by equipment remaining connected to the transformer as well as by external conditions, while the internal relationship between aging and moisture had not be explored. Belén García and Juan Carlos Burgos' studies [20][21][22] focused on moisture diffusion in oil-paper insulation, and explored the influence of temperature, thickness of cardboard, aging and other factors on moisture diffusion coefficient between oil and paper. The mechanism of factors affecting water diffusion was elaborately demonstrated, which revealed an internal relation between moisture and aging degree of paper.…”