Journal ArticleDOI
Power transformer insulation – history, technology and design
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TLDR
A review of the history of paper and pressboard insulation for electric insulation of oil immersed power transformers is given in this paper, along with a list of factors important for the manufacturing and operation of reliable transformers.Abstract:
This paper reviews briefly the history of paper and pressboard insulation being used for electric insulation of oil immersed power transformers. An introduction to today's insulation technique is given. Important details of materials selection, as well as drying, clamping and oil impregnation procedures required to achieve short-circuit resistant windings are explained. Aging effects are described, as they gradually weaken the solid insulation mechanically and electrically. The value of post-mortem analysis of transformers before scrapping is shown with examples. A list of factors important for the manufacturing and operation of reliable transformers, yet often neglected, completes this article.read more
Citations
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Journal ArticleDOI
A review of critical evaluation of natural ester vis-a-vis mineral oil insulating liquid for use in transformers: Part II
TL;DR: In this article, the authors compared the green insulating liquid with existing mineral oil technology in terms of environmental concern, fire safety, physio-chemical properties, thermal performance, and dielectric performance and concluded that natural esters are acceptable for new transformers and for retro filling existing units.
Journal ArticleDOI
Space charge behavior in the sample with two layers of oil-immersed-paper and oil
TL;DR: In this article, a waveform recovery method was proposed to get rid of the effects of interface and anisotropy on PEA result, and the space charge distributions in the two-layer samples under different voltage and oil thicknesses were measured.
Journal ArticleDOI
Derating of transformers under non-linear load current and non-sinusoidal voltage – an overview
TL;DR: In this paper, a review of derating of transformers under non-sinusoidal operation is presented, for which all available approaches are classified into four major methods including IEEE recommended, analytical, experimental and finite elements based methods.
Journal ArticleDOI
Thermal management of a distribution transformer: An optimization study of the cooling system using CFD and response surface methodology
TL;DR: In this paper, a numerical scheme has been developed to examine the effective parameters on thermal management of distribution transformers and subsequently to optimize their cooling systems, and the accuracy of the numerical model was established via comparing the numerical results with the measured temperatures of a running transformer.
Journal ArticleDOI
Solid state transformers: concepts, classification, and control
Mohammed Azharuddin Shamshuddin,Felix Rojas,Roberto Cardenas,Javier Pereda,Matias Diaz,Ralph Kennel +5 more
TL;DR: This paper provides a complete overview on SST: concepts, topologies, classification, power converters, material selection, and key aspects for design criteria and control schemes proposed in the literature.
References
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Journal ArticleDOI
Aging of oil-impregnated paper in power transformers
TL;DR: In this article, the effects of moisture, oxygen, and acidity upon the aging of Kraft and thermally upgraded ("Insuldur/spl reg/") papers have been studied in detail.
Journal ArticleDOI
Degradation of cellulosic insulation in power transformers. Part 3: effects of oxygen and water on ageing in oil
TL;DR: In this article, the effects of heat, water and oxygen on cellulose insulation degradation in electrical transformers have been studied over a number of years using degree of polymerization (DP) of the paper as a measure of ageing.
Journal ArticleDOI
Degradation of cellulosic insulation in power transformers. Part 2: formation of furan products in insulating oil
TL;DR: In this paper, the analysis of furan degradation products in transformer oil provides a complementary technique to dissolved gas analysis for monitoring transformer condition, and the main products of the ageing are 2-furfuryl alcohol, 2-furaldehyde (furfural), 2-acetylfuran and 5-methylfurfural.
Journal ArticleDOI
Statistical Dielectric Degradation of Large-Volume Oil-Insulation
TL;DR: In this paper, a study was carried out under well defined conditions of the oil quality, particularly with regard to the degree of particle contamination, and the results indicated that both the electrode area and the stressed oil volume can affect the dielectric strength of transformer oil, with the stressed-oil-volume effect being most pronounced under particle contamination conditions.
Proceedings ArticleDOI
Thermally upgraded insulation in transformers
TL;DR: In this article, the development of thermally upgraded paper is reviewed and various chemical modifications developed and give the current processes used today, as well as the effect of thermal upgraded insulations on diagnostic techniques such as gas-in oil analysis of furanic compounds.