DocumentCode :
1100987
Title :
Corrosive Sulfur Induced Failures in Oil-Filled Electrical Power Transformers and Shunt Reactors
Author :
Scatiggio, F. ; Tumiatti, V. ; Maina, R. ; Tumiatti, M. ; Pompili, M. ; Bartnikas, R.
Author_Institution :
TERNA, Venice
Volume :
24
Issue :
3
fYear :
2009
fDate :
7/1/2009 12:00:00 AM
Firstpage :
1240
Lastpage :
1248
Abstract :
The nature and causes of corrosive sulfur induced failures are examined in oil-filled transformers and shunt reactors. Copper sulfide, which is formed when the corrosive sulfur in a mineral oil reacts with the copper conductors, is likely to diffuse into the paper tapes insulating the conductors. Since copper sulfide is partially conducting, the dielectric losses of the contaminated oil-impregnated-paper tapes are markedly increased; paper tapes in close proximity to the copper conductors are found to attain tan delta values > 1.0 even at room temperature. It is highly likely that thermal instabilities develop at those sites at operating temperatures, leading to increased loss currents and, ultimately, short circuits between the turns. This sequence of events is substantiated by evidence from the field, which indicates large areas of thermally degraded insulations and charred breakdown regions along the coils, the extent of which becomes more pronounced at higher operating temperatures (toward the top of the windings).
Keywords :
copper compounds; corrosion; failure analysis; power transformer insulation; reactors (electric); sulphur; transformer oil; contaminated oil-impregnated-paper tapes; copper conductor insulator; copper sulfide; corrosive sulfur-induced failures; oil-filled electrical power transformers; short circuits; shunt reactors; Conductors; Copper; Dielectric losses; Dielectrics and electrical insulation; Inductors; Minerals; Petroleum; Power transformers; Shunt (electrical); Temperature; Corrosive sulfur; dibenzyl disulfide (DBDS); failures; oil insulation; standardization; transformers/shunt reactors;
fLanguage :
English
Journal_Title :
Power Delivery, IEEE Transactions on
Publisher :
ieee
ISSN :
0885-8977
Type :
jour
DOI :
10.1109/TPWRD.2008.2005369
Filename :
5109873
Link To Document :
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