Improving the modelling of the water content of power transformer insulation in the frequency domain

Martin, Daniel, Krause, Olav, Saha, Tapan and Feely, Col (2015). Improving the modelling of the water content of power transformer insulation in the frequency domain. In: 2015 IEEE 11th International Conference on the Properties and Applications of Dielectric Materials (ICPADM). International Conference on the Properties and Applications of Dielectric Materials (ICPADM), Sydney, NSW, Australia, (60-63). 19-22 July 2015. doi:10.1109/ICPADM.2015.7295208


Author Martin, Daniel
Krause, Olav
Saha, Tapan
Feely, Col
Title of paper Improving the modelling of the water content of power transformer insulation in the frequency domain
Conference name International Conference on the Properties and Applications of Dielectric Materials (ICPADM)
Conference location Sydney, NSW, Australia
Conference dates 19-22 July 2015
Convener IEEE Dielectrics and Electrical Insulation Society (IEEE-DEIS)
Proceedings title 2015 IEEE 11th International Conference on the Properties and Applications of Dielectric Materials (ICPADM)
Journal name Proceedings of the IEEE International Conference on Properties and Applications of Dielectric Materials
Place of Publication Piscataway, NJ, United States
Publisher IEEE (Institute for Electrical and Electronic Engineers)
Publication Year 2015
Sub-type Fully published paper
DOI 10.1109/ICPADM.2015.7295208
Open Access Status Not Open Access
ISBN 9781479989034
ISSN 2160-9241
Volume 2015-October
Start page 60
End page 63
Total pages 4
Language eng
Formatted Abstract/Summary
One technique to measure the water content of the insulation of an operating transformer is to use online water activity sensors with cellulose adsorption isotherms. In a cellulosic pressboard/paper insulation system, the water migrates between the cellulose and oil until a known equilibrium partition is reached, when the cellulose adsorption isotherms can be used to estimate the water content of pressboard from the concentration of water dissolved in the oil. However, a significant drawback is that the time constants involved in the diffusion of water through pressboard are very high, and it is very unlikely that the transformer will be at one temperature long enough for the water partition to reach equilibrium. In the past this has been resolved by using long term averages. However, an obvious question is for how long a long term average should be applied for before it filters out actual features of the measurement data, and how short it may be to suppress the short term fluctuations. We set out resolve this question by analysing the frequency spectrum of the water content of pressboard calculations for an operating power transformers. This showed a difference between the very low frequencies attributable to the migration of water, and the higher frequencies caused by the daily temperature cycling of the transformer. A low pass filter was then applied to the measurement data. This technique was found to be more effective than using a long term average, although further research is required to optimise such a filter.
Q-Index Code E1
Q-Index Status Confirmed Code
Institutional Status UQ

 
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Created: Fri, 20 Nov 2015, 22:17:23 EST by Dr Olav Krause on behalf of School of Information Technol and Elec Engineering