Journal ArticleDOI
Statistical Dielectric Degradation of Large-Volume Oil-Insulation
TLDR
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.Abstract:
In an attempt to clarify the persisting controversy over the effect of the electrode area versus that of the stressed oil volume in large-oil-volume- breakdown, a study was carried out under well defined conditions of the oil quality, particularly with regard to the degree of particle contamination. The results indicate 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. Test results with technically clean transformer oil as currently accepted for use in power apparatus indicate that the degree of particle contamination in these oils is sufficient to produce an observable stressed-oil-volume effect. Finally, it is demonstrated that the observed phenomenon can be interpreted in terms of an apparent effect of either the electrode area or the stressed oil volume. This has led to the development of a semi-empirical method of quantitatively assessing the breakdown phenomenon in large oil volumes with reasonable accuracy.read more
Citations
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Journal ArticleDOI
Streamer generation and propagation in transformer oil under AC divergent field conditions
Olivier Lesaint,R. Tobazeon +1 more
TL;DR: In this paper, a detailed study of transformer oil under AC voltage in different field configurations, ranging from very divergent point-plane geometry to quasi-uniform fields produced by rods or spheres, is presented.
Journal ArticleDOI
Prebreakdown phenomena in dielectric liquids
TL;DR: In this paper, the authors make a synthesis of characteristic features of pre-breakdown phenomena in liquids, e.g., those events which precede arc development, and demonstrate the advantages of using a point-plane electrode geometry to study separately cathodic and anodic prebreakdown stages.
Journal ArticleDOI
Statistical investigation of AC breakdown voltage of nanofluids compared with mineral and natural ester oil
Georgios D. Peppas,Vasilios P. Charalampakos,Eleftheria C. Pyrgioti,Michael G. Danikas,Aristides Bakandritsos,Ioannis F. Gonos +5 more
TL;DR: In this article, three different insulating liquids, natural ester, mineral oil which is currently used by the Public Power Corporation of Greece and a nanofluid of surface coated Fe3O4 nanoparticles, were subjected to AC voltage stress and their statistical breakdown voltage was measured and compared.
Journal ArticleDOI
Power transformer insulation – history, technology and design
TL;DR: 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.
Journal ArticleDOI
Breakdown of transformer oil
TL;DR: Some of the factors affecting the dielectric strength of transformer oil are investigated in this article, including the stabilization phenomenon, oil and electrode pretreatment, the effect of oil velocity, capacitance parallel to the test cell, and the effects of electrode area and gap spacing.
References
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Journal ArticleDOI
Electrode Design for Testing in Uniform Field Gaps
TL;DR: In this article, the efficiency of producing uniform fields in the test gap was evaluated for practical electrode configurations corresponding to the plane, the Rogowski and the Bruce profiles, and the results obtained show a pronounced end effect at plane-profile electrodes.
Journal ArticleDOI
A Fundamental Factor Controlling the Unit Dielectric Strength of Oil [includes discussion]
Journal ArticleDOI
Breakdown of Transformer Oil
Y. Kawaguchi,H. Murata,M. Ikeda +2 more
TL;DR: In this paper, the authors tried to express the breakdown stress of transformer oil as a function of stressed oil volume, but their results were limited to their respective electrodes, and the latters made it difficult to predict break-down voltage from electrostatic field, as made for air and S F6 gaps.
Journal ArticleDOI
Electric strength of transformer oil for large electrode areas
TL;DR: In this article, the effects of temperature, forced oil motion and the nature of gas in solution are studied, and it is concluded that the oil flow is an important parameter in determining the statistical distribution of breakdown measurements.
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