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

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4433 ◽  
Author(s):  
Grzegorz Dombek ◽  
Zbigniew Nadolny ◽  
Piotr Przybylek ◽  
Radoslaw Lopatkiewicz ◽  
Agnieszka Marcinkowska ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Linear Equation ◽  
Heat Transport ◽  
Mineral Oil ◽  
Experimental Database ◽  
Synthetic Ester ◽  
Dielectric Liquids ◽  
Paper Insulation ◽  
The Impact ◽  
Natural Ester

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.

scholarly journals On parameterization of heat conduction in coupled soil water and heat flow modelling

2012 ◽  
Vol 7 (No. 4) ◽  
pp. 125-137 ◽  
Author(s):  
J. Votrubová ◽  
M. Dohnal ◽  
T. Vogel ◽  
M. Tesař
Keyword(s):  
Thermal Conductivity ◽  
Soil Water ◽  
Heat Transport ◽  
Preferential Flow ◽  
Thermal Conditions ◽  
Industrial Applications ◽  
Soil Thermal Conductivity ◽  
Vegetation Season ◽  
Simulation Results ◽  
The Impact

Soil water and heat transport plays an important role in various hydrologic, agricultural, and industrial applications. Accordingly, an increasing attention is paid to relevant simulation models. In the present study, soil thermal conditions at a mountain meadow during the vegetation season were simulated. A dual-continuum model of coupled water and heat transport was employed to account for preferential flow effects. Data collected at an experimental site in the Šumava Mountains, southern Bohemia, during the vegetation season 2009 were employed. Soil hydraulic properties (retention curve and hydraulic conductivity) determined by independent soil tests were used. Unavailable hydraulic parameters were adjusted to obtain satisfactory hydraulic model performance. Soil thermal properties were estimated based on values found in literature without further optimization. Three different approaches were used to approximate the soil thermal conductivity function, λ(θ): (i) relationships provided by Chung and Horton (ii) linear estimates as described by Loukili, Woodbury and Snelgrove, (iii) methodology proposed by Côté and Konrad. The simulated thermal conditions were compared to those observed. The impact of different soil thermal conductivity approximations on the heat transport simulation results was analysed. The differences between the simulation results in terms of the soil temperature were small. Regarding the surface soil heat flux, these differences became substantial. More realistic simulations were obtained using λ(θ) estimates based on the soil texture and composition. The differences between these two, related to neglecting vs. considering λ(θ) non-linearity, were found negligible.

scholarly journals Dielectric properties of natural ester, synthetic ester midel 7131 and mineral oil diala D

2014 ◽  
Vol 21 (2) ◽  
pp. 644-652 ◽  
Author(s):  
Yi Jing ◽  
Igor Timoshkin ◽  
Mark Wilson ◽  
Martin Given ◽  
Scott Macgregor ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Mineral Oil ◽  
Synthetic Ester ◽  
Natural Ester

Aging of Paper Insulation in Natural Ester & Mineral Oil

2012 ◽  
Vol 2 (3) ◽  
pp. 141-146 ◽  
Author(s):  
Yunus Biçen ◽  
Yusuf Çilliyüz ◽  
Faruk Aras ◽  
Guzide Aydugan
Keyword(s):  
Mineral Oil ◽  
Paper Insulation ◽  
Natural Ester

scholarly journals Influence of Aging Derivatives on Properties of Natural Ester Oil

2020 ◽  
Vol 9 (4) ◽  
pp. 2597-2600 ◽  
Keyword(s):  
Mineral Oil ◽  
Transformer Oil ◽  
Critical Parameters ◽  
Uv Spectrum ◽  
Service Period ◽  
Before And After ◽  
Furanic Compounds ◽  
Paper Insulation ◽  
Transmission And Distribution ◽  
Natural Ester

Transformers are the critical component in the power system, which is used for transmission and distribution purposes. Traditionally mineral oil has been used as the liquid insulation medium in the transformer. Owing to poor bio - degradability and availability, it has been widely studied to replace mineral oil with natural ester oil. During the service period of the transformer, oil insulation and paper insulation gets degraded due to aging. This aging results in the formation of furanic compounds in the oil insulation, which will affect the performance of oil insulation and thus the transformer life. In this proposed work, an effort is made to analyze the critical parameters before and after the inclusion of an aging derivative of 2–furfuraldehyde (2-FAL). 2-FAL has been added in the proportion of 20 ppm to investigate the oil’s properties such as breakdown voltage, viscosity, flash point, fire point, and peak absorbance of the UV spectrum. It is observed that there is a lesser impact on the properties with the addition of 20ppm of 2-FAL. Hence it is suggested that the various concentration of 2-FAL may be added to check the quality of oil for further applications.

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