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Applied Computational Intelligence and Soft Computing
Volume 2012 (2012), Article ID 525494, 5 pages
http://dx.doi.org/10.1155/2012/525494
Research Article

Analyzing Ferroresonance Phenomena in Power Transformers Including Zinc Oxide Arrester and Neutral Resistance Effect

1Electrical Engineering Department, Islamic Azad University, Takestan Branch, Takestan, Ghazvin 1995755681, Iran
2Electrical Engineering Department, Amirkabir University of Technology, Tehran, Iran

Received 19 April 2012; Accepted 25 June 2012

Academic Editor: F. Morabito

Copyright © 2012 Hamid Radmanesh and Fathi Seyed Hamid. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper studies the effect of zinc oxide arrester (ZnO) and neutral earth resistance on controlling nonconventional oscillations of the unloaded power transformer. At first, ferroresonance overvoltage in the power system including ZnO is investigated. It is shown this nonlinear resistance can limit the ferroresonance oscillations but it cannot successfully control these phenomena. Because of the temperature dissipation of ZnO, it can withstand against overvoltage in a short period and after that ferroresonance causes ZnO failure. By applying neutral earth resistance to the system configuration, mitigating ferroresonance has been increased and chaotic overvoltage has been changed to the smoother behavior such as fundamental resonance and periodic oscillation. The simulation results show that connecting the neutral resistance exhibits a great mitigating effect on nonlinear overvoltage.