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

Grzegorz Dombek,Andrzej Tomczewski,Zbigniew Nadolny,Tomasz Boczar,Lukasz Druzynski,Piotr Przybylek,Radoslaw Lopatkiewicz,Agnieszka Marcinkowska

doi:10.3390/en13174433

Grzegorz Dombek, Andrzej Tomczewski + Show 6 more

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https://doi.org/10.3390/en13174433

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Abstract

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.

Highlights

The power system is a collection of devices for the generation, transmission, distribution, storage, and use of electricity
Coefficient of Unimpregnated thermal conductivity λ can be determined from the relationship [56]: Table 2 presents the results of measurements of the thermal conductivity of unimpregnated cellulose paper and unimpregnated aramid paper Pdepending on the temperature
Based on the obtained results, it was found that the same moisture content of paper insulation caused a greater increase in the thermal conductivity of cellulose paper than aramid paper

Summary

Introduction

The power system is a collection of devices for the generation, transmission, distribution, storage, and use of electricity. Enabling the delivery of electricity for households, enterprises, and public utilities in a continuous and uninterrupted manner is based primarily on the functional connection and appropriate maintenance of this strategic infrastructure. From the point of view of the transmission and distribution of electricity, power transformers play an important role. Knowledge of the condition of the transformer is necessary to achieve maximum return on investment, as well as to minimize the costs associated with its operation [1,2]. The efficiency of transformers depends mainly on the state of their insulation system [5,6,7]. The insulation system is a type of “transformer heart”. Due to the fact that it consists of solid (cellulose and aramid paper) and Energies 2020, 13, 4433; doi:10.3390/en13174433 www.mdpi.com/journal/energies

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