Modeling the Insulation Paper Drying Process from Thermogravimetric Analyses

Bétié, A.; Meghnefi, F.; Fofana, I.; Yéo, Z.

doi:10.3390/en11030517

Cited by 11 publications

(10 citation statements)

References 15 publications

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“…The water content in oil-paper insulation increases with the transformer lifetime. Its presence may contribute to the degradation of the transformer insulation system by accelerating the aging processes occurring in it [19,20], which increases the probability of failure. Due to the role of power transformers and distribution transformers in the power system, this is a particularly significant problem [3,21].…”

Section: Introductionmentioning

confidence: 99%

“…Moisture in transformer windings insulation can cause some problems during operation, e.g., aging and electrical breakdown between its windings. Since transformer paper insulation carries a large portion of moisture, knowledge of water content in this part is essential [1,19,22]. Therefore, appropriate numerical multiphysical approaches [23][24][25] e.g., with ANSYS or COMSOL, constitutive thermal (e.g., thermal conductivity) and electrical (e.g., resistivity, breakdown voltage) material parameters and models are needed [26].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Moisture on the Thermal Conductivity of Cellulose and Aramid Paper Impregnated with Various Dielectric Liquids

et al. 2020

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This paper presents the effect of the impact of moisture in paper insulation used as insulation of transformer windings on its thermal conductivity. Various types of paper (cellulose and aramid) and impregnated (mineral oil, synthetic ester, and natural ester) were tested. The impact of paper and impregnated types on the changes in thermal conductivity of paper insulation caused by an increase in moisture were analyzed. A linear equation, describing the changes in thermal conductivity due to moisture, for various types of paper and impregnated, was developed. The results of measuring the thermal conductivity of paper insulation depending on the temperature are presented. The aim of the study is to develop an experimental database to better understand the heat transport inside transformers to assess aging and optimize their performance.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Moisture on the Thermal Conductivity of Cellulose and Aramid Paper Impregnated with Various Dielectric Liquids

et al. 2020

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“…The conventional drying method consists of heating the insulation system in the dryer by using hot air and reducing the pressure. The insulation system is heated to a temperature of 85-130 • C. After heating, the pressure in the dryer is lowered to below 1 mbar, which results in an increase in the rate of water evaporation [27]. Unfortunately, the evaporation of water is accompanied by a decrease in the temperature of the insulation.…”

Section: Drying Methods Of Transformer Insulationmentioning

confidence: 99%

A New Concept of Applying Methanol to Dry Cellulose Insulation at the Stage of Manufacturing a Transformer

Przybyłek

2018

Energies

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A decisive technical challenge for transformer manufacturers is correctly drying the cellulose insulation. During the production of a transformer, it is necessary to reduce its insulation’s moisture content from about 8% to less than 1% in the shortest possible time period. The drying of insulation is a time-consuming process, and for high-power transformers, it can last up to three weeks. Several drying techniques are used during the production of a transformer, and all of them require heating up the insulation to a high temperature and applying a vacuum. Unfortunately, the use of a high drying temperature above 100 °C can cause a decrease in the degree of cellulose polymerization by over a dozen percentage points. This paper presents a new concept for drying cellulose insulation that does not require heating insulation and applying a vacuum. In this solution, methanol is used as the drying medium. The research results showed the possibility of drying cellulose insulation by means of methanol with different initial moisture contents. The possibility of completely drying pressboard of various thicknesses for a sufficient period of time was also proven. The paper also presents a new concept of both the device and the procedure for drying cellulose insulation by means of methanol.

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“…A mathematical model describing the kinetics of drying according to temperature, initial moisture, paper weight, final moisture, and extraction rate is proposed by Betie et al [4], based on thermogravity analyses. The impact of moisture, weight, and temperature on the drying process has been investigated.…”

Section: A Review Of the Special Issuementioning

confidence: 99%