Next Article in Journal
Analysis of Analytical Models Developed under the Uniaxial Strain Condition for Predicting Coal Permeability during Primary Depletion
Previous Article in Journal
Novel Carbon Materials in the Cathode Formulation for High Rate Rechargeable Hybrid Aqueous Batteries
Article Menu
Issue 11 (November) cover image

Export Article

Open AccessArticle
Energies 2017, 10(11), 1843; https://doi.org/10.3390/en10111843

A Simplified Top-Oil Temperature Model for Transformers Based on the Pathway of Energy Transfer Concept and the Thermal-Electrical Analogy

1
Faculty of Engineering, Universiti Pertahanan Nasional Malaysia, Kem Sg Besi 57000, Malaysia
2
Centre for Electromagnetic and Lightning Protection Research, Universiti Putra Malaysia, Serdang 43400, Malaysia
3
Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
4
Faculty of Engineering Technology, Universiti Teknikal Malaysia Melaka, Durian Tunggal 76100, Malaysia
5
Malaysia Transformer Manufacturing Sdn. Bhd, Ampang 54200, Selangor, Malaysia
*
Author to whom correspondence should be addressed.
Received: 28 September 2017 / Revised: 23 October 2017 / Accepted: 24 October 2017 / Published: 11 November 2017
(This article belongs to the Section Electrical Power and Energy System)
Full-Text   |   PDF [5290 KB, uploaded 11 November 2017]   |  

Abstract

This paper presents an alternative approach to determine the simplified top-oil temperature (TOT) based on the pathway of energy transfer and thermal-electrical analogy concepts. The main contribution of this study is the redefinition of the nonlinear thermal resistance based on these concepts. An alternative approximation of convection coefficient, h, based on heat transfer theory was proposed which eliminated the requirement of viscosity. In addition, the lumped capacitance method was applied to the thermal-electrical analogy to derive the TOT thermal equivalent equation in differential form. The TOT thermal model was evaluated based on the measured TOT of seven transformers with either oil natural air natural (ONAN) or oil natural air forced (ONAF) cooling modes obtained from temperature rise tests. In addition, the performance of the TOT thermal model was tested on step-loading of a transformer with an ONAF cooling mode obtained from previous studies. A comparison between the TOT thermal model and the existing TOT Thermal-Electrical, Exponential (IEC 60076-7), and Clause 7 (IEEE C57.91-1995) models was also carried out. It was found that the measured TOT of seven transformers are well represented by the TOT thermal model where the highest maximum and root mean square (RMS) errors are 6.66 °C and 2.76 °C, respectively. Based on the maximum and RMS errors, the TOT thermal model performs better than Exponential and Clause 7 models and it is comparable with the Thermal-Electrical 1 (TE1) and Thermal-Electrical 2 (TE2) models. The same pattern is found for the TOT thermal model under step-loading where the maximum and RMS errors are 5.77 °C and 2.02 °C. View Full-Text
Keywords: top-oil temperature thermal model; pathway of energy transfer; thermal-electrical analogy; nonlinear oil thermal resistance; transformers top-oil temperature thermal model; pathway of energy transfer; thermal-electrical analogy; nonlinear oil thermal resistance; transformers
Figures

Figure 1

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 (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Roslan, M.H.; Azis, N.; Kadir, M.Z.A.A.; Jasni, J.; Ibrahim, Z.; Ahmad, A. A Simplified Top-Oil Temperature Model for Transformers Based on the Pathway of Energy Transfer Concept and the Thermal-Electrical Analogy. Energies 2017, 10, 1843.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Energies EISSN 1996-1073 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top