Measuring the pressboard water content of transformers using cellulose isotherms and the frequency spectrum of water migration

Martin, Daniel, Krause, Olav and Saha, Tapan (2016) Measuring the pressboard water content of transformers using cellulose isotherms and the frequency spectrum of water migration. IEEE Transactions on Power Delivery, . doi:10.1109/TPWRD.2016.2524022


Author Martin, Daniel
Krause, Olav
Saha, Tapan
Title Measuring the pressboard water content of transformers using cellulose isotherms and the frequency spectrum of water migration
Journal name IEEE Transactions on Power Delivery   Check publisher's open access policy
ISSN 0885-8977
1937-4208
Publication date 2016-02-03
Sub-type Article (original research)
DOI 10.1109/TPWRD.2016.2524022
Open Access Status Not Open Access
Total pages 7
Place of publication Piscataway, NJ, United States
Publisher Institute of Electrical and Electronics Engineers
Collection year 2017
Language eng
Abstract The measurement of water within power transformer insulation is necessary for the unit’s reliable operation. Probes can be inserted in to the oil of a transformer to measure water activity, and then this water activity is used to determine the water content of transformer cellulosic insulation. The migration of water between the insulation media is driven by differences in water vapor pressure around the insulation system. Over time, this water reaches an equilibrium partition when cellulosic adsorption isotherms are used to calculate the concentration of water absorbed by the cellulose. However, the insulation of a normally operating transformer is highly unlikely to reach this state, as the migration of water between the insulation media is much slower than the rate of change of temperature caused by the varying load of the transformer. This leads to inaccuracies in analyzing water vapor pressure, which is a function of both oil water content and temperature. The frequency spectrum of the oil’s water activity data was used to determine whether very slow changes in dissolved water, attributed to long diffusion time constants, could be separated by a filter from fast changes caused by temperature, leading to a better measurement technique. This filter was then used on data from three operating power transformers, which had had their insulation water content measured using dielectric response. The results are discussed in this article.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Information Technology and Electrical Engineering Publications
 
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Created: Fri, 12 Feb 2016, 12:34:47 EST by Dr Olav Krause on behalf of School of Information Technol and Elec Engineering