Artificial Neural Networks Application for Top Oil Temperature and Loss of Life Prediction in Power Transformers

Abstract

The development of precise tools for power transformers temperature prediction allows a better use of equipment’s nominal capacity, extending its useful life and possibility of strategic planning based on possible future operating scenarios. Proposition of temperature prediction models is of great interest to those responsible for power transformers. This article presents the development of Artificial Neural Networks (ANNs) as a tool for top oil temperature prediction in power transformers and justifies the use of Non-linear AutoRegressive with eXogenous inputs (NARX) model and input parameters according to the thermal behavior of the transformers under study. Also, a comparison from the perspective of the loss of life between the ANNs response and monitoring data is made, as the prediction for fictitious future operating scenarios is presented for method validation. The results obtained demonstrate that the developed ANNs replicate in a very satisfactory way the thermal behavior of the transformers under study. Error remains small during most of the prediction horizon, approximately 2 °C in absolute values (about 4% nominal). Allowing operators to assess dispatch among their equipment, extending the useful life and avoiding unexpected situations, featuring a very useful tool in power plants and substations and opening paths for new studies.

Keywords:

• artificial neural networks
• NARX
• temperature prediction
• top-oil temperature
• power transformers
• loss of life

Acknowledgments

This research was carried out with the support of CAPES/PROEX—Financing Code 001. The authors would also like to thank Santo Antônio Energia (P&D Project PD-06683-0318/2018), VEGOOR, Federal University of Santa Maria—UFSM, UFSM Electrical Engineering Post-Graduation Program (PPGEE) and National Institute of Science and Technology–Distributed Generation (INCT–GD) by technical and financial support for this work.

Additional information

Funding

This work was funded by Agência Nacional de Energia Elétrica.

Notes on contributors

Antônio Mário Kaminski

Antônio Mário Kaminski received the B.S. in Automation and Control Engineering and M.S. in Electrical Engineering from Federal University of Santa Maria (UFSM), Brazil, in 2018 and 2020 respectively. Since 2018 works at Smart Grids Institute (INRI) in Santa Maria, Brazil, with focus on power and distribution transformers. Presently, he is an Electrical Engineering doctoral student at Federal University of Santa Maria and his fields of research are thermal models, loss of life, and high frequency transitory models for power transformers.

Leonardo Hautrive Medeiros

Leonardo Hautrive Medeiros M.S. in Electrical Engineering at the Federal University of Santa Maria (UFSM) in 2020 and graduated in Electrical Engineering at UFSM in 2017. He is currently a Doctoral Student at UFSM. His fields of interest are: distribution transformers, power transformers, thermal behavior of transformers, dielectric behavior of transformers, behavior of electromechanical stresses in transformers, efficiency of transformers, thermal analysis of devices, Finite Elements Method (FEM), and Computational Fluid Dynamics (CFD).

Vitor Cristiano Bender

Vitor Cristiano Bender Electrical Engineer from the Regional University of the Northwest of the State of Rio Grande do Sul (UNIJUÍ), Ijuí, Brazil, in 2011, M.S. and PhD in Electrical Engineering from the Federal University of Santa Maria (UFSM), Santa Maria, Brazil, in 2012 and 2015, respectively. In 2014 he completed a doctoral internship at the Universidad de Oviedo, Gijón, Spain. From 2015 to 2017, he was a professor at the Federal University of Pampa (UNIPAMPA), Alegrete, Brazil. Since 2018, he has been a professor at the Department of Electronics and Computing at UFSM, where he also serves as coordinator of the computer-aided engineering and high-voltage laboratories. His research interests include electric power components and systems.

Tiago Bandeira Marchesan

Tiago Bandeira Marchesan Graduated in Electrical Engineering from the Federal University of Santa Maria (UFSM) in 2003, and PhD in Electrical Engineering in 2007 from the same University, with an internship at the Universidad de Oviedo, España. He has been director of the UFSM Technology Center since 2017. He is a Professor of the Post-Graduate Program in Electrical Engineering and a professor at the Department of Electromechanics and Power Systems at the same University. His fields of interest are power systems, with focus on power transformers.

Micael Márcio Oliveira

Micael Márcio Oliveira Graduated in Electrical Engineering from the Federal University of Pampa (UNIPAMPA), Brazil, in 2019 with an internship at Zhejiang University, China. Received the M.S. in electrical engineering from the Federal University of Santa Maria in 2021. He has experience in Electrical Engineering, with emphasis on electrical machines, energy efficiency, automation of electrical and industrial processes, distribution transformers, power transformers, thermal behavior of transformers, loss of life of transformers and insulating oil analysis. He is currently a doctoral student in Electrical Engineering at UFSM, carrying out research in the area of power transformers.

Daniela Maia Bueno

Daniela Maia Bueno Graduated in Electrical Engineering from the Federal University of Pampa (UNIPAMPA), Brazil, in 2019 and received an M.S. in electrical engineering from UFSM in 2021. His research areas focus on the study of insulation life of power transformers.

José Batista Ferreira Neto

José Batista Ferreira Neto Graduated in Electrical Engineering with focus on Automation from Uberaba University, UNIBEI, in 2006. He has extensive work experience in the Brazilian electricity sector, where he currently serves as operations manager at the Santo Antônio hydroelectric plant in Porto Velho, Brazil. His areas of interest are protection, control, communication and operation of electrical systems.

Helena Maria Wilhelm

Helena Maria Wilhelm Received a Licentiate and Bachelor’s Degree in Chemistry from the Federal University of Paraná (UFPR) in 1993, a M.S. in Chemistry from the Federal University of Santa Catarina (UFSC) in 1996 and a PhD in Chemistry from the State University of Campinas (2000). She is currently the director of the research and innovation unit at VEGOOR Tecnologia Aplicada. She has experience in the field of Chemistry, with an emphasis on Physical Chemistry, working mainly on the following topics: insulating papers and fluids for energy transformers, insulating vegetable oil, insulating mineral oil and SF6.