A bibliographic analysis of transformer literature 1990-2000

This paper presents an analysis of the bibliography on transformers covering the period from 1990 to 2000. It contains all the transformer subjects: a) Transformer design, b) Transformer protection, c) Transformer connections, d) Transformer diagnostics, e) Transformer failures, f) Transient analysis of transformers (overvoltages, overcurrents), g) Modeling and analysis of transformer using FEM (thermal modeling, losses modeling, insulation modeling, windings modeling). Several international journals were investigated including the following: Advances in Electrical and Computer Engineering, Canadian Journal of Electrical and Computer Engineering, COMPEL (The International Journal for Computation and Mathematics in Electrical and Electronic Engineering), Electrical Engineering, Electric Power Components and Systems, Electric Power Systems Research, European Transactions on Electrical Power, IEEE Transactions on Magnetics, IEEE Transactions on Power Delivery, International Journal of Electrical Power and Energy Systems, and IET Generation Transmission & Distribution. Due to the high number of publication in journals, we are not considering publications of conferences and symposia. A total of 700 publications are analyzed in this paper. The research presented in this paper is important because it contains and analyzes the best research papers on transformers coming from many countries all over the world and published in top rated scientific electrical engineering journals

Analysis of slots in horizontal plates of T-beams in shell-form power transformers

A systematic analysis of the use of slots to reduce stray losses in the horizontal plates of the T-beams in shell-form power transformers is presented. In the paper, the horizontal plate of T-beams is modeled as a rectangular stainless steel plate subjected to a perpendicular uniform magnetic field generated by a Merritt coil. The results are compared with the values given by an analytical formula for calculating the losses in a stainless steel plate without slots. The following important design alternatives are analyzed and discussed: (1) plates with rounded slots; (2) plates with unrounded slots; (3) effect of width and length of one slot; (4) effect of the distance between slots; (5) effect of number of slots. It has been found that substantial loss reduction can be obtained when drilling a few slots. Measurements of flux densities were done for seven shell-form power transformers. Using the measurements we calculated the losses in the plates using formula. Using the results of the design alternatives the efficiency of the use of slots in plates of real T-beams was demonstrated. Finally, a structural analysis was made to study the impact of slots in an experimental slotted T-beam. (C) 2013 Elsevier B.V. All rights reserved

Study of parameters influencing the performance of connectors used for load and temperature tests on transformers

This paper emphasizes the factors to be considered when designing power connectors used in the load and temperature tests of power transformers. External conductors used to perform load and temperature tests in transformers are referred as power connectors in this contribution. Electrical and thermal investigations of a single-phase shell-type, 300 MVA, 400 kV-21.5 kV power transformer connector were performed. To analyze the behavior of the connector, a harmonic analysis to calculate losses by Joule effect generated in the electrical connector was first performed, followed by a thermal, finite element based analysis to determine temperature distribution. As heat sources, harmonic losses analyses were performed. Temperature distribution obtained by the finite element simulation was compared with measurements recorded by an infrared camera during the tests