Title :
Influence of surface roughness and thickness of pressboard on the charging characteristics of transformer oil
Author :
Poovamma, P.K. ; Jagadish, R.
Author_Institution :
Central Power Res. Inst., Bangalore, India
Abstract :
Flow electrification has been found to be the principal cause of at least a dozen of failures of forced oil cooled power transformers. Despite considerable research efforts worldwide, the phenomena is still posing a threat to the service reliability. The present study carried out employing pressboards and presspapers of varying compositions, roughness and thickness, adopting Rotating Disc Electrode (RDE) and Rotating Cylindrical Electrode (RCE) systems revealed higher charging of Paraffinic based oil with pressboards composed of cotton pulp. Charging of the oil also increased with thickness of the solid insulating material. It was noticed that the charging of the oil increased with pressboards and presspapers with their surface calendered. The surface roughness (Ra) of pressboards investigated varied from 2 μm-10 μm. The investigation carried out using RDE failed to influence the charging of oil with roughness of pressboard. The study was carried out over rotational speed of 120-2000 rpm and temperature ranging from 27°C-60°C
Keywords :
power transformer insulation; surface charging; surface topography; transformer oil; 27 to 60 C; Rotating Cylindrical Electrode; Rotating Disc Electrode; charging; cotton pulp; failures; flow electrification; forced oil cooled power transformers; paraffinic based oil; pressboard; presspapers; service reliability; solid insulating material; surface roughness; thickness; transformer oil; Cotton; Electrodes; Oil insulation; Petroleum; Power system reliability; Power transformers; Rough surfaces; Solids; Surface charging; Surface roughness;
Conference_Titel :
Electrical Insulation, 1994., Conference Record of the 1994 IEEE International Symposium on
Conference_Location :
Pittsburgh, PA
Print_ISBN :
0-7803-1942-7
DOI :
10.1109/ELINSL.1994.401402
