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Influence of oil aging on the motion characteristics of cellulose particles and conductivity in contaminated mineral oil and natural ester under DC electric field
Author(s) -
Liao Ruijin,
Dan Min,
Hao Jian,
Yang Lijun,
Li Yanqing
Publication year - 2018
Publication title -
ieej transactions on electrical and electronic engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.254
H-Index - 30
eISSN - 1931-4981
pISSN - 1931-4973
DOI - 10.1002/tee.22776
Subject(s) - mineral oil , electric field , saturation (graph theory) , materials science , moisture , cellulose , electrical resistivity and conductivity , composite material , contamination , conductivity , environmental science , chemistry , metallurgy , engineering , electrical engineering , organic chemistry , ecology , physics , mathematics , combinatorics , quantum mechanics , biology
Abstract Natural esters are beginning to be utilized as transformer oil, so certain problems happening during their operation need to be solved urgently. To explore the effect of pollution on the insulation performance of oil, in this paper we investigate the motion characteristics of cellulose particles and conductivity in a mineral oil and a natural ester. The influence of oil aging, DC electric filed strength, and moisture content of the cellulose particles is considered. It is found hat with increasing electric field strength, aging of the oil, and moisture of the particles, the motion of cellulose particles becomes more obvious. The bridging velocity becomes higher and stable bridges grow more compact. The saturation current in the contaminated oil increases exponentially with the electric field strength. The saturation current in the contaminated natural ester is smaller than that in the contaminated mineral oil under the same electric field and particle concentration, especially when the oil is aged. For the mineral oil, the ratio of the conductivity current in contaminated oil to that in clean oil is higher under a lower electric field. However, the situation is opposite in the case of the natural ester. Fewer cellulose bridges and lower saturation current imply that the natural ester has a better insulation property and resistance to pollution. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.