The influence of moisture on the electrical properties of polymeric insulating materials for outdoor high voltage application
Basic investigations concerning the moisture absorption and the resulting variations of the electrical characteristics of polymeric insulating materials for outdoor application are reported.
First, under special consideration of the various outdoor conditions, a survey of aging effects on polymers is given. The second part deals with the experimental set-ups, the measuring devices as well as the selection of the materials being tested.
The water absorption capability of the selected materials is reported when subjected to atmospheres of different relative humidities, or when immersed into distilled water of different temperatures. The results offer fundamental differences between filled and unfilled polymers. Observed structural changes due to hydrolysis and swelling are discussed in connection with the chemical constitution of the materials under test.
Together with the accumulated water, the chemical changes take influence on the dielectric properties. So, both the loss tangent and the permittivity as well as the do conductivity and the breakdown strength are strongly affected. The investigation of the electrical strength was performed by using newly developed test specimen which allow to determine the influence of humidity on the intrinsic strength. To clarify the breakdown mechanism under wet condition the measurement and evaluation of the pre-breakdown current turned out to be of importance.Lesen Sie die deutsche Zusammenfassung auf Kunststoffe.de
Degradation, permittivity, dissipation factor, high voltage outdoor insulator, dielectric break down, water absorption, DC conductivity, silicon rubber, epoxy resin, PTFE, EPR
Institute / chair: Institut für Hochspannungstechnik der Technischen Universität Carolo-Wilhelmina zu Braunschweig
Technical consultant for expert services: Prof. Dr.-Ing. Hermann Kärner (Betreuer), Prof. Dr. rer. nat. Günter Lautz
Publication year: 1984
Provider: Wissenschaftlicher Arbeitskreis Kunststofftechnik (WAK) / Kunststoffe.de
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