Basic research of highly viscous silicone paste and -liquids regarding their dielectric strenght and dissipation factor

Summary

Silicone pastes are used as assembly aid of HV cable accessories especially stress-cones whereas silicone liquids finds its use as insulating liquid in transformers and other HV equipment. The most important electrical properties are breakdown strength and dissipation factor at 50-Hz-AC and conductivity in the DC-field. The breakdown strength and dissipation factor of silicone fluid can be measured using specific test equipment according to several standards. However, most of this test equipment’s are only capable to measure low-viscosity-oils (<150 mm²/s). For silicone pastes, there is no suitable test equipment available neither to determine the breakdown strength nor the dissipation factor. This paper reports about the development of test devices to determine the electrical breakdown strength and the dissipation factor of silicone pastes and higher viscosity silicone fluids at 50-Hz-AC voltage. The first results of the dissipation factor show, that the silicone paste is comparable to other standard organic insulation materials whereas the high viscosity silicone fluid shows a slightly different behaviour. The breakdown strength of the silicone paste showed comparable high values assumed the paste is clean and homogeneous without any air bubbles. The developed test devices have shown very reproducible test results regarding the dielectric properties of the pastes and oils, in a wide range of tests.

Additional informations

Authors

ANNAKAGE, MORSHUIS, MEHAIRJAN, ZHUANG

Keywords

silicon paste, dielectric properties, high viscous silicon liquids, test devices