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Modelling of electromagnetic processes in transformer windings under the influence of internal network overvoltage

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Category: Electrical engineering

Last Updated on Thursday, 13 November 2014 10:36

Published on Thursday, 13 November 2014 10:36

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Authors:

L.O. Nykonets, Dr.Sci.(Tech), Professor, National University “Lviv Polytechnic”, Professor of the Department of Electrical Supply to Industry, Cities and Agriculture, Lviv, Ukraine

M.M. Molnar, National University “Lviv Polytechnic”, Assistant Lecturerof the Department of Electrical Supply to Industry, Cities and Agriculture, Ukraine

M.B. Sabat, National University “Lviv Polytechnic”, Assistant Lecturerof the Department of Electrical Supply to Industry, Cities and Agriculture, Lviv, Ukraine

I.R. Buchkovskyi, National University “Lviv Polytechnic”, Postgraduate Student of the Department of Electrical Supply to Industry, Cities and Agriculture, Lviv, Ukraine

Abstract:

Purpose. Formation of the transformer mathematical model that adequately recreates electromagnetic processes in transformer windings under the influence of internal network overvoltage, and study of electromagnetic processes in transformer windings with using this model.

Methodology. The model of the transformer is obtained basing theoretical principles of electrical engineering, which don’t require any experimental study of real electromagnetic processes inside equipment for adequacy confirmation of mathematical models, taking into consideration transformer construct elements (winding, magnetic core, insulation), and mutual inductance among winding parts.

Findings. Methods of transformer mathematical models synthesis, which take into consideration mutual induction between winding parts by modelling reactive components of winding impedance with opposite signs have been developed. Electromagnetic processes in certain points of a high-voltage winding of the transformer in different modes of operation are studied using the developed mathematical models of a power transformer.

Scientific novelty. The methodology allows formation of electrical equipment with high voltage windings mathematical models, which take into consideration parameters distribution and allow studying electromagnetic processes inside windings, without experimental research of real electromagnetic processes inside electrical equipment for model adequacy confirmation.

Practical value. For the first time Power engineering field obtains a tool for evaluation of quantitative indicators of electromagnetic processes in a random point of a high voltage winding of a distributed-parameters transformer with mutual induction between its elements, which is influenced by network internal random frequency overvoltage. The tool can be used during all design, production, test and electrical equipment operation stages.

References:

1. Межгосударственный стандарт. Электрооборудование и электроустановки переменного тока на напряжение 3кВ и выше. Общие методы испытаний электрической прочности изоляции: ГОСТ 1516.2-97. – К.: Госстандарт Украины, 1999. – 32 с.

Interstate standard, “AC electrical equipment and installations with rated voltage 3 kV and higher. Main test methods of electrical strength of insulation”, State Standard 1516.2–97,(1999), Statestandard of Ukraine, Kyiv.

2. Межгосударственный стандарт, электрооборудование переменного тока на напряжение от 1 до 750кВ. Требования к электрической прочности изоляции: ГОСТ 1516.3–96. – К.: Госстандарт Украины, 1999.

Interstate standard, “Alternative current electrical equipment with rated voltage from 1 to 750 kV. Insulation electrical strength requirements”, State Standard 1516.3–96, (1999), State standard of Ukraine, Kyiv.

3. Ахметшин Р.С. Технические средства диагностирования силовых трансформаторов 10/0,4кВ на основе частотных характеристик / Р.С. Ахметшин, Л.М. Рыбаков // Электричество. – 2005. – № 5.– С. 20–26

Ahmetshin, R.S. and Rybakov, L.M. (2005), “Technical tools of 10/0,4 kV power transformers diagnostic which based on frequency characteristic”, “Electricity”, № 5, pp. 20–26.

4. СегедаМ.С. Математичне моделювання вільних коливань напруги в обмотках трансформаторів з урахуванням взаємоіндукції між витками під час імпульсних перенапруг/ М.С. Сегеда, Є.В. Черемних,Т.А. Мазур// Науковий вісник НГУ–2013. – № 1. С. 68–76.

Segeda, M.S., Cheremnyh, E.V., Mazur, T.A. (2013), “Mathematical modelling of voltage free oscillation in transformer windings taking into consideration mutual induction between turns under the influence of impulse overvoltage”, Dnepropetrovsk, Scientific Bulletin of National Mining University, no. 1, pp. 68–76.

5. Electrical environment of transformers. Impact of fast transients. Prepared by CIGRE JWG A2-A3-B3.21. (FORMERJWG12-13-23.21), ELECTRA, (2005), Vol. 2, no. 218, pp. 28–37.

6. Физические явления внутреннего резонанса в электрооборудовании с обмотками высокого напряжения: монография/ [Бучковський И.Р., Молнар М.М., Никонец А.Л. и др.] – Львов: Друк НВФ  „Українські технології“,2012.– 166 с.

Buchkovsky, I.R., Molnar, M.M., Nykonets, A.L., Nykonets, L.A. and Sabat, M.B. [Physical Phenomenon of Internal Resonance in Electrical Equipment with High Voltage Windings], Monography,“Ukrainian technologies”, Lviv, Ukraine.

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2014-11-10  132.79 KB  792

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