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eng Classic Power Transformer Windings
Sanchez, Jean
Transformers Magazine Vol. 1, No. 2, 2014
The main function of any transformer is to adapt two or more different voltage levels, one being the high voltage (HV), the other being the low voltage (LV). Sometimes a medium voltage (MV) is needed in between, then one winding for every voltage level and every phase are manufactured. Most of the inner parts of the transformer can be named the “active part”, and on it, the “heart” of the transformers is composed of the windings which work on the principle of mutual induction. The main power transformer winding technologies principles will be...
Hrčak ID: 186584


eng Supply chain complexity in power transformer industry
Kivrak, Ufuk
Transformers Magazine Vol. 6, No. 5, 2019
The complexity of the supply chain in transformer industry is usually not well understood. This article aims to create a better insight into this area by analyzing the characteristics of supply markets for power transformer industry, the product characteristics and by defining appropriate supply chain. Finally, some of the methods for supply chain optimization are described.
Hrčak ID: 228363


eng Insulating liquid properties impacting transformer performance
Wolmarans, Carl; Pahlavanpour, Bruce
Transformers Magazine Vol. 6, No. 1, 2019
This paper briefly discusses the functions of a power transformer’s insulating liquid in achieving effective cooling and reliable performance under high voltage stress, and in having sufficient oxidation stability to maintain performance, as well as low maintenance. Low viscosity over operating temperature range, high oxidation stability and favourable streamer propagation behaviour characterized by high acceleration voltage are key aspects of a good insulating liquid. The efficiency of a power transformer can be partly improved by increased co...
Hrčak ID: 218741


eng A century of dissolved gas analysis - part III
Grisaru, Marius
Transformers Magazine Vol. 7, No. 1, 2020
With time, the size of the transformer increased exponentially both in power andvoltage. Although huge improvements have been made regarding the magnetic core and the decrease of core losses, a transformer is now producing much more heat due to the design optimization and size reduction. Heat reduces the insulating properties of the insulating matrix, reducing the conducting properties and accelerating all chemical reactions including ageing and corrosion. The stresses from the insulation materials increase gradually. In the last century, th...
Hrčak ID: 232078


eng INSULATION OPTIMIZATION OF POWER TRANSFORMER LEADS
Marković, Mladen
Journal of Energy Vol. 63, No. 1-4, 2014
Power transformers reliability, amongst other things, depends on its insulation system. High voltage leads are a part of the insulation system and should be properly insulated. This includes positioning an insulation barrier between the leads and a tank on a certain distance. This distance affects the safety factors (breakdown probability) for such system. The paper presents optimization process with which both the breakdown probability and leads vs. tank distance could be minimized. It also proposes a method with which this optimization p...
Hrčak ID: 199251


eng INSULATION OPTIMIZATION OF POWER TRANSFORMER LEADS
Marković, Mladen
Journal of Energy Vol. 63, No. 1-4, 2014
Power transformers reliability, amongst other things, depends on its insulation system. High voltage leads are a part of the insulation system and should be properly insulated. This includes positioning an insulation barrier between the leads and a tank on a certain distance. This distance affects the safety factors (breakdown probability) for such system. The paper presents optimization process with which both the breakdown probability and leads vs. tank distance could be minimized. It also proposes a method with which this optimization p...
Hrčak ID: 199252


eng Measurement of Circulating Currents in Split- Winding Transformer and Comparison with Numerical Calculation
Štrac, Leonardo; Haramustek, Juraj; Dorešić, Matej; Švarc, Davor; Jurišić, B.
Journal of Energy Vol. 68, No. 4, 2019
Split-winding transformer is a one of the common transformer types with one low-voltage winding placed above the other low-voltage winding and with the jointly high-voltage and regulation winding. The paper investigates circulating currents that occur in high-voltage and regulation windings in case of nonsymmetric load. In addition, measurement of circulating currents for a case of 240MVA, 220 kV transformer is presented along with a numerical calculation of circulating currents and compared with the measurement.
Hrčak ID: 247106


eng Estimating current and future transformers markets
Aubertin, Steve
Transformers Magazine Vol. 3, No. 3, 2016
The globalisation of the power and distribution transformers markets and the increase of available market data has presented manufacturers with a new twist on an old problem. How to obtain accurate information about the current and future markets? This article explores some of the issues and reviews some of the sources.
Hrčak ID: 202312


eng Europe, North America and China: The future and is Brexit at all relevant
Aubertin, Steve
Transformers Magazine Vol. 4, No. 2, 2017
There are very few similarities between transformer markets in Europe, North America and China; however, together these account for 64 % of the global transformer market. Analysis of imports and exports of these individual markets reveals their nature and the bonds among them, and in the end, leads to a somewhat surprising conclusion.
Hrčak ID: 202381


eng Short-circuit withstand capability of power transformers - Part I
Smeets, Rene
Transformers Magazine Vol. 4, No. 2, 2017
This article discusses verification of the ability of a transformer to survive short circuit. Fault current leads to large axial and radial forces on windings, which have to be managed by proper structural design. Test experience, showing a failure rate of 20-25 % of well-prepared transformers, suggests that the highest degree of reliability with respect to short-circuit withstand verification is ensured through full-scale testing in accordance with the international standards. The prime failure mode is winding deformation, but many other defic...
Hrčak ID: 179590