Effect of moisture migration on surface discharge on oil-pressboard of power transformers under cooling

In this paper, the PD properties of an ester oil/PB and a mineral oil/PB system undergoing a moisture transient are investigated using a needle-plane electrode under natural cooling. The temperature, moisture concentration and water activity of the oil are continuously monitored. Moreover, an improv...

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Bibliographic Details
Published inIEEE transactions on dielectrics and electrical insulation Vol. 27; no. 5; pp. 1743 - 1751
Main Authors Jiang, J. P., Du, B. X., Cavallini, A.
Format Journal Article
LanguageEnglish
Published New York IEEE 01.10.2020
The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
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Summary:In this paper, the PD properties of an ester oil/PB and a mineral oil/PB system undergoing a moisture transient are investigated using a needle-plane electrode under natural cooling. The temperature, moisture concentration and water activity of the oil are continuously monitored. Moreover, an improved moisture diffusion model is developed by using COMSOL Multiphysics to verify the experimental results. The measurement results show that there is a sharp reduction of partial discharge inception voltage (PDIV) or a sudden increase of PD intensity in the process of natural cooling for both ester oil and mineral oil system. However, the PDs extinguish gradually after the occurrence of the minimum of PDIV. For the cooling mode selected in this study, the minimum of PDIV for the ester oil system appears in the third hour after cooling begins, while it is about in the second hour for the mineral oil system. In addition, the simulation results are consistent with the experimental data.
ISSN:1070-9878
1558-4135
DOI:10.1109/TDEI.2020.008965