Thermal Analysis of Power Transformer Using an Improved Dynamic Thermal Equivalent Circuit Model

Abstract

—To insure the health of power transformers insulation, its heat distribution in different operating conditions must be determined. In extended thermal equivalent circuits (TECs), less attention has been paid to losses and temperature distribution of different parts such as core, tank and metallic regions of transformer. Most previous works, hot-spot temperature of winding and top-oil were considered by available no-load and on-load losses of transformer. This paper extends the TEC to be able to evaluate fully the different operating conditions of transformer. Estimation of losses of different elements of transformer as heat generating source and thermal parameters of transformer are introduced as two major challenges of the proposed model. At this end, an appropriate three-dimensional finite element method is used to estimate the losses of different components of power transformer. In addition, to identify the transformer thermal parameters, a genetic algorithm is used by searching in chosen measurements. Finally, the results obtained by the TEC are compared with IEEE-Annex G method and measured temperature and high accuracy of the proposed model in temperature estimation in different parts of transformer are shown.

Keywords:

• power transformers
• equivalent circuit
• finite elements method

Additional information

Notes on contributors

Morteza Mikhak-Beyranvand

Morteza Mikhak-Beyranvand received the B.Sc. degree from Hadaf University, in 2010, the M.Sc. degrees from Malek-ashtar University of Technology, in 2013, and Ph.D. degrees from Lorestan University, in 2019, all in electrical engineering (in Iran). His research interests include design and analysis of electrical machines and electromagnetic-thermal modeling of power transformers.

Jawad Faiz

Jawad Faiz received the Ph.D. degree in electrical engineering from the University of Newcastle upon Tyne, UK in 1988. He became an Assistant Professor in 1988, an Associate Professor in 1992, and a Full Professor in 1998 at the University of Tabriz. Since February 1999, he has been working as a Professor in the School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Iran. He is also the director of Center of Excellence on Applied Electromagnetic Systems since 2003. He was the Dean of the Faculty of Engineering, at University of Tabriz for 7 years and vice dean of College of Engineering in the University of Tehran for 7 years. Professor Faiz is an IEEE Senior Member, Member of Iran Academy of Sciences and Member of Euro-Med. Academy of Art and Sciences. He received a number of International and National awards. His current research includes design of electrical machines, fault diagnosis of electrical machines and analysis of transformers performance.

B. Rezaeealam

B. Rezaeealam received the B.Sc. degree from Isfahan University of Technology in 1997, the M.Sc. and Ph.D. degrees from University of Tehran in 2000 and 2005, respectively, all in electrical engineering. He is currently an associate professor in the department of electrical engineering, Lorestan University, Iran. His research interests include modeling and design using FEM, electrical machines and drives.