Research topics at the Professorship High Voltage Engineering and Switchgear Technology

Insulating materials with nanofillers (nanocomposites)

Polymeric insulating materials which contain few percent by weight of nanofillers (< 10 wt. %) are called nanocomposites. Such nanocomposites can exhibit improved electrical and dielectric properties compared to unfilled materials and materials with a huge amount (approximately 50 wt. %) of microfillers. This is attributed to a spatially extended interaction zone, the so called interphase, which can be formed between the filler particles and the polymer matrix. Because of the high ratio of surface to volume for nanoparticles the interphase can take a remarkable percentage of the whole composite material in nanocomposites, even for small filling degrees. Therefore its properties can be decisive for the properties of the composite material.
There are several models existing for the description of the interphase. Using electrostatic force microscopy the interphase could be made visible for the first time and its extension could be determined in own research work. In further research projects the interphase shall be characterised electrically and chemically with appropriate methods. With respect to tailor made materials with an extended interphase the factors of influence on the formation of an interphase around nanofillers shall be clarified.

For further information please contact: Annika-Sophie Rempe, M.Sc., Marlene Stuefer, M.Sc.

New insulating gases for gas-insulated metal enclosed switchgear

For many decades sulfur-hexafluoride (SF6) has been used as insulating gas with good arc-extinction properties in gas-insulated metal-enclosed switchgear (GIS) and circuit breakers. Presently, the high global warming potential (GWP) of SF6 is motivating a worldwide search for environmentally friendly alternatives. Promising alternative gases with dielectric properties comparable to SF6 have a high dew point, and can be used in GIS as gas mixtures together with carrier gases only. As a precondition for their practical use, characteristic properties of alternative gases and their mixtures have to be examined. The focus of the research project with the new insulating gases is on the insulating capacity of different electrode arrangements with different gas mixtures relevant for high voltage application, the influence of gas liquefaction and the modeling of discharge development.

For further information, please contact: Michael Peiß, M.Sc.