Comparison of the electric and dielectric behaviour of different insulating fluids

authored by

Manfred Beyer , H. Borsi

Abstract

The authors consider ester fluid Midel 7131 and silicon fluid for use in distribution transformers. The electric and dielectric properties of the two fluids were determined in new condition and after an aging period of 1000 h under severe conditions. The dielectric dissipation factor tan δ was almost the same for the silicon and ester fluid in the temperature range between 0 and 120°C. A temperature change from 20 to 120°C increased these values from about 7 × 10^-2 to about 3 × 10^-1. The dielectric strength of the fluids is highly dependent on humidity. A 1000-h aging process at 150°C under the influence of 3 g/l Cu, 3 g/l Fe, 3 g/l Al, and atmospheric oxygen caused an increase in tan δ by two orders of magnitude, whereas there was no significant change to be observed with the silicon fluid. The electric strength was reduced for both fluids by a 1000-h aging process. The effect of this aging process was more pronounced with the silicon fluid than with the ester fluid.

Organisation(s)

High Voltage Engineering and Asset Management Section (Schering Institute)

Type

Paper

Pages

524-528

No. of pages

5

Publication date

1990

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General Engineering