Cover Image

Using a dynamic thermal model approach to estimate loss of life of mineral oil-immersed transformers

Transformers are among the most important equipment in electrical power systems, where their operations play the main roles in providing the reliable power systems. Because of the high cost of transformers and their permanent connections to the transmission and distribution systems, reliable measure...

Full description

Saved in:
Bibliographic Details
Main Author: Sedehi Esfahani, Mohammad Tolou Askari
Format: Thesis
Language:English
Published: 2010
Online Access:http://psasir.upm.edu.my/id/eprint/26671/1/FK%202010%2089R.pdf
http://psasir.upm.edu.my/id/eprint/26671/
Tags: Add Tag
No Tags, Be the first to tag this record!
id my.upm.eprints.26671
record_format eprints
spelling my.upm.eprints.266712013-10-24T00:53:39Z http://psasir.upm.edu.my/id/eprint/26671/ Using a dynamic thermal model approach to estimate loss of life of mineral oil-immersed transformers Sedehi Esfahani, Mohammad Tolou Askari Transformers are among the most important equipment in electrical power systems, where their operations play the main roles in providing the reliable power systems. Because of the high cost of transformers and their permanent connections to the transmission and distribution systems, reliable measures are needed to extend the life span. Insulation life of the transformer and loading capabilities depend on several parameters, among which cooling mode, ambient temperature, oil viscosity are critical. Hot spot temperature is a major factor on the insulation life of the transformer. To predict the hot spot temperature and top oil temperature, many principal models have been proposed such as the classic thermal model, and thermal-electrical models. This research attempts to determine an accurate hot spot temperature, hence evaluate the loss of life of the transformer according to the numerical analysis method. Top oil temperature and hot spot temperature were determined by an accurate thermal model which takes into account the dynamic parameters such as ambient temperature, oil viscosity, winding losses, and loading profile. IEEE standards and thermal-electrical model, which are regarded as the two acceptable and reliable thermal models, have been used as underlying principles of this research. Both linear and non-linear regressions have been used for solving these thermal models. The Runge-Kutta numerical method is proposed in this study for solving the thermal model and for carrying out the work on different types of the transformer based on the data that have been collected from heat run tests, loading profile and electrical and physical characteristics of each transformer. An alternative solution for solving the thermal model is proposed in this study. Results are compared with the actual temperature and hot spot temperature in the IEEE standards. Since data has been collected from different types of electrical transformers, this thesis proposes a model which is based on the previous researches that are carried out on 187 MVA, 2.5 MVA, 30 MVA and 250 MVA transformers. The prediction of top oil temperature and hot spot temperature is very important for estimating the loss of life of the transformer in the system. Therefore, such an accurate technique is needed for solving the thermal models. The findings reveal that the uses of numerical methods are in good agreement with the measured values when comparing with the traditional methods. In addition, based on the theoretical definition and results obtained, the proposed fourth order Runge-Kutta has given reasonably good accuracy among other numerical methods such as the second order Runge-Kutta and Euler methods. This has led to an improvement in calculating the top oil temperature and hot spot temperature, as well as in predicting the loss of life of the transformer. 2010-05 Thesis NonPeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/26671/1/FK%202010%2089R.pdf Sedehi Esfahani, Mohammad Tolou Askari (2010) Using a dynamic thermal model approach to estimate loss of life of mineral oil-immersed transformers. Masters thesis, Universiti Putra Malaysia.
institution Universiti Putra Malaysia
building UPM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Putra Malaysia
content_source UPM Institutional Repository
url_provider http://psasir.upm.edu.my/
language English
description Transformers are among the most important equipment in electrical power systems, where their operations play the main roles in providing the reliable power systems. Because of the high cost of transformers and their permanent connections to the transmission and distribution systems, reliable measures are needed to extend the life span. Insulation life of the transformer and loading capabilities depend on several parameters, among which cooling mode, ambient temperature, oil viscosity are critical. Hot spot temperature is a major factor on the insulation life of the transformer. To predict the hot spot temperature and top oil temperature, many principal models have been proposed such as the classic thermal model, and thermal-electrical models. This research attempts to determine an accurate hot spot temperature, hence evaluate the loss of life of the transformer according to the numerical analysis method. Top oil temperature and hot spot temperature were determined by an accurate thermal model which takes into account the dynamic parameters such as ambient temperature, oil viscosity, winding losses, and loading profile. IEEE standards and thermal-electrical model, which are regarded as the two acceptable and reliable thermal models, have been used as underlying principles of this research. Both linear and non-linear regressions have been used for solving these thermal models. The Runge-Kutta numerical method is proposed in this study for solving the thermal model and for carrying out the work on different types of the transformer based on the data that have been collected from heat run tests, loading profile and electrical and physical characteristics of each transformer. An alternative solution for solving the thermal model is proposed in this study. Results are compared with the actual temperature and hot spot temperature in the IEEE standards. Since data has been collected from different types of electrical transformers, this thesis proposes a model which is based on the previous researches that are carried out on 187 MVA, 2.5 MVA, 30 MVA and 250 MVA transformers. The prediction of top oil temperature and hot spot temperature is very important for estimating the loss of life of the transformer in the system. Therefore, such an accurate technique is needed for solving the thermal models. The findings reveal that the uses of numerical methods are in good agreement with the measured values when comparing with the traditional methods. In addition, based on the theoretical definition and results obtained, the proposed fourth order Runge-Kutta has given reasonably good accuracy among other numerical methods such as the second order Runge-Kutta and Euler methods. This has led to an improvement in calculating the top oil temperature and hot spot temperature, as well as in predicting the loss of life of the transformer.
format Thesis
author Sedehi Esfahani, Mohammad Tolou Askari
spellingShingle Sedehi Esfahani, Mohammad Tolou Askari
Using a dynamic thermal model approach to estimate loss of life of mineral oil-immersed transformers
author_facet Sedehi Esfahani, Mohammad Tolou Askari
author_sort Sedehi Esfahani, Mohammad Tolou Askari
title Using a dynamic thermal model approach to estimate loss of life of mineral oil-immersed transformers
title_short Using a dynamic thermal model approach to estimate loss of life of mineral oil-immersed transformers
title_full Using a dynamic thermal model approach to estimate loss of life of mineral oil-immersed transformers
title_fullStr Using a dynamic thermal model approach to estimate loss of life of mineral oil-immersed transformers
title_full_unstemmed Using a dynamic thermal model approach to estimate loss of life of mineral oil-immersed transformers
title_sort using a dynamic thermal model approach to estimate loss of life of mineral oil-immersed transformers
publishDate 2010
url http://psasir.upm.edu.my/id/eprint/26671/1/FK%202010%2089R.pdf
http://psasir.upm.edu.my/id/eprint/26671/
_version_ 1643828981280014336
score 13.211869

Similar Items