A Study on Overvoltage Distribution Across the High Voltage Winding of an Electric Power Transformer

Gloria Ciumbulea¹, Lavinia Iordache (Bobaru)¹, Sorin Deleanu^2, , Mihai Iordache¹, Neculai Galan¹, Scott Basinger³, Gregory Von Lipinski² and David Carpenter⁴

¹“POLITEHNICA” University of Bucharest, Bucharest, Romania

²Northern Alberta Institute of Technology, Edmonton, Canada

³Eaton Corporation, Edmonton, Canada

⁴GE’s Grid Software Solutions, Technical Training Institute, Redmond, Washington, USA

Cite this paper

Gloria Ciumbulea, Lavinia Iordache (Bobaru), Sorin Deleanu, Mihai Iordache, Neculai Galan, Scott Basinger, Gregory Von Lipinski and David Carpenter. A Study on Overvoltage Distribution Across the High Voltage Winding of an Electric Power Transformer. American Journal of Electrical and Electronic Engineering. 2016; 4(4):110-122. doi: 10.12691/AJEEE-4-4-2

Abstract

The main objective of this paper is to represent effects of overvoltage on a transformer winding by analysis and modelling with special attention given to the voltage distribution across the winding. The authors have considered both approaches in modelling the winding: windings with distributed electrical parameters, and secondly disk coils with concentrated parameters. All known models are assembled in a general model based upon distributed parameters, while the excitation voltages display sinusoidal variation in time (commutation) or step. Both induced and commutation voltages, applied across the transformer winding, will generate free oscillations which are analyzed further on. According to the model, the transformer’s windings are divided in several disk coils with concentrated known parameters. This results in a complete electrical network used for simulations. All simulations have been performed using the software package SYSEG (SYmbolic State Equation Generation). Using SYSEG package, from the state equations assembled in terms of the disk coils voltages, one can obtain the overvoltage across the transformer winding as function of time. If the frequency of the commutation voltage and the frequency of the free oscillations are in close range, then the voltage across the disk coils shows a non-uniform distribution. An important aspect of this paper is accounting for asymmetry of the transformer by modelling the reinforced insulation of the first turns of the disk coils of the transformer’s high voltage winding. This affects the value of the inter-turn capacitance of these coils, and is an aspect which is treated in our simulations.

Keywords

transformer, overvoltage, modeling, disk coils, simulation, resonance

Copyright

This work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

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