Development of low-permittivity pressboard and its evaluation for insulation of oil-immersed EHV power transformers

Author

Kamata, Y. ; Ohe, E. ; Endoh, K. ; Furukawa, S. ; Tsukio, H. ; Maejima, M. ; Fujita, H. ; Nozaki, M. ; Ishizuka, F. ; Hyohdoh, K.

Author_Institution

Hitachi Ltd., Tokyo, Japan

Volume

26

Issue

4

fYear

1991

fDate

8/1/1991 12:00:00 AM

Firstpage

819

Lastpage

825

Abstract

The development of a low-permittivity pressboard obtained by blending polymethylpentene fiber with cellulose fiber is described. The permittivity is 3.5, which is lower than that of conventional pressboard. With this pressboard, insulating characteristics of intercoil models were investigated under lightning impulse and AC voltage conditions. It is demonstrated that a spacer fabricated from this pressboard material increases the partial discharge inception and breakdown voltages up to 30% compared with conventional pressboard spacers

Keywords

electric breakdown of solids; organic insulating materials; permittivity; transformer insulation; AC voltage conditions; breakdown voltages; cellulose fiber; insulation; intercoil models; lightning impulse; low-permittivity pressboard; oil-immersed EHV power transformers; partial discharge inception; polymethylpentene fiber; Dielectrics and electrical insulation; Lightning; Oil insulation; Partial discharges; Permittivity; Petroleum; Power transformer insulation; Power transformers; Stress; Voltage;

fLanguage

English

Journal_Title

Electrical Insulation, IEEE Transactions on

Publisher

ieee

ISSN

0018-9367

Type

jour

DOI

10.1109/14.83708

Filename

83708