Title :
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
fDate :
8/1/1991 12:00:00 AM
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;
Journal_Title :
Electrical Insulation, IEEE Transactions on
