Study on Thermal Ageing Characteristics of Silicone Rubber and Pressboard in Mineral Oil

Conference: VDE-Hochspannungstechnik 2018 - ETG-Fachtagung
11/12/2018 - 11/14/2018 at Berlin, Deutschland

Proceedings: ETG-Fb. 157: VDE-Hochspannungstechnik

Pages: 6Language: englishTyp: PDF

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Karambar, Smitha; Tenbohlen, Stefan (University of Stuttgart, Institute of Power Transmission and High Voltage Technology (IEH), Stuttgart, Germany)

Silicone rubbers are widely used as outdoor insulators due to their excellent electrical, mechanical and thermal properties. Investigations have been carried out to determine the influence of mineral oil on silicone rubber. This research aims to investigate the thermal ageing characteristics of different silicone rubbers and pressboard in mineral oil (NYTRO LYRA X) and their influence on dielectric properties of mineral oil. Properties of three different types of silicone rubbers, namely, insulative silicone rubber, conductive silicone rubber, silicone rubber with conductive and insulative layers have been investigated in this research. The solid insulation materials are immersed in mineral oil and are thermally aged at 130deg C in airtight glass bottles for 360 hours. Samples of mineral oil without any solid insulation materials are also prepared and are aged under similar conditions. After thermal ageing, mineral oil and solid insulation samples are investigated for their dielectric properties. Mineral oil samples are investigated for their moisture content, dissipation factor, breakdown voltage and dissolved gases. Whereas, solid insulation samples are tested for their moisture content. In this paper, the measurement results for different samples are compared and analyzed. The experimental results demonstrate that the dielectric properties of mineral oil largely depends on the type of solid insulation material used during the ageing test.