UPM Institutional Repository

A simplified top-oil temperature model for transformers based on the pathway of energy transfer concept and the thermal-electrical analogy


Citation

Roslan, Muhammad Hakirin and Azis, Norhafiz and Kadir, Mohd Zainal Abidin Ab and Jasni, Jasronita and Ibrahim, Zulkifli and Ahmad, Azalan (2017) A simplified top-oil temperature model for transformers based on the pathway of energy transfer concept and the thermal-electrical analogy. Energies, 10 (11). pp. 1-15. ISSN 1996-1073

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.


Download File

[img] Text
A Simplified Top-Oil Temperature Model for Transformers Based on the Pathway of Energy Transfer Concept and the Thermal-Electrical Analogy.pdf
Restricted to Repository staff only

Download (5MB)
Official URL or Download Paper: https://www.mdpi.com/1996-1073/10/11/1843

Additional Metadata

Item Type: Article
Divisions: Faculty of Engineering
Institute of Advanced Technology
DOI Number: https://doi.org/10.3390/en10111843
Publisher: MDPI
Keywords: Top-oil temperature thermal model; Pathway of energy transfer; Thermal-electrical analogy; Nonlinear oil thermal resistance; Transformers
Depositing User: Mohd Hafiz Che Mahasan
Date Deposited: 05 Nov 2018 01:23
Last Modified: 05 Nov 2018 01:23
Altmetrics: http://www.altmetric.com/details.php?domain=psasir.upm.edu.my&doi=10.3390/en10111843
URI: http://psasir.upm.edu.my/id/eprint/63579
Statistic Details: View Download Statistic

Actions (login required)

View Item View Item