DocumentCode :
1338539
Title :
The gassing tendency of various insulating fluids under electrical discharge
Author :
Cho, J. S N ; Fofana, I. ; Beroual, A. ; Aka-Ngnui, T. ; Sabau, J.
Author_Institution :
AMPERE, Ecole Centrale de Lyon, Ecully, France
Volume :
18
Issue :
5
fYear :
2011
fDate :
10/1/2011 12:00:00 AM
Firstpage :
1616
Lastpage :
1625
Abstract :
Since gas evolvement deteriorates the dielectrical properties of insulating fluid, its ability to resist decomposition under electrical discharge is of paramount importance for the safety of power transformers under operating conditions. In this paper, a series of experiments have been performed under electrical discharge according to ASTM D6180. Various insulating fluids were considered. The samples include minerals oils, synthetic and natural esters, and silicone fluid. The results indicate that the gassing tendency of natural esters is much lower than their counterparts. No significant differences between synthetic esters and silicone fluid were observed. Severely hydrotreated and hydrocracked oils indicate a higher gassing tendency. It is also shown that service-aged oil gassing tendency decreases with reclamation passes. The reclamation of service aged oil by three commercially available Fuller´s Earth (FE) showed a declined gassing tendency when FE helped reducing the DDF and turbidity. In addition, the theoretical premises that, oil born decay products contribute to the oil gassing, is experimentally confirmed under laboratory conditions. Extended stability test (3 times longer than the standard specification) also provide convincing evidences that each brand of mineral insulating oil might contain a limited amount of unstable hydrocarbons and volatile compounds. This finding indicates that when in service conditions these are gradually decomposed, the gassing tendency should go down.
Keywords :
decomposition; discharges (electric); insulating oils; power transformer insulation; power transformer protection; silicone insulation; transformer oil; turbidity; ASTM D6180; dielectrical property; electrical discharge; fuller earth; hydrocracked oil; hydrotreated oil; insulating fluid; mineral oil; natural ester; power transformer safety; service-aged oil gassing tendency; silicone fluid; synthetic ester; unstable hydrocarbon compound; Chemicals; Dielectric liquids; Discharges; Fluids; Hydrocarbons; Minerals; Vegetable oils; Fuller´s earth; Insulating fluids; dissolveddecay products; electrical discharge; gassing tendency; reclamation; stability test; turbidity;
fLanguage :
English
Journal_Title :
Dielectrics and Electrical Insulation, IEEE Transactions on
Publisher :
ieee
ISSN :
1070-9878
Type :
jour
DOI :
10.1109/TDEI.2011.6032832
Filename :
6032832
Link To Document :
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