Research Focus at High Voltage Engineering and Asset Management

As a result of the liberalization of the electrical energy supply, the need for and interest in measures to increase reliability, optimized maintenance and extended service life of operating equipment (assets) have increased significantly in recent years. For this purpose, reliability and maintenance models of electrical equipment and networks are of particular importance. Based on the data collected by condition monitoring, an AI (artificial intelligence) system should evaluate the actual condition of the asset and provide information on what the risk of failure is, e.g., as a result of detected faults within the components or due to aging caused by electrical, thermal and mechanical stresses. Taking various models into account, all maintenance measures can then be optimized to minimize the risk of failure and thus maximize operational reliability. The research work in progress at the Schering Institute is concerned with the development of the fundamentals necessary for such asset management (AM) and the optimization of AM strategies with the aid of mathematical models.

Solid insulating materials for medium- and high voltage applications as well as in the field of electromobility are permanently optimized, adapted and newly developed, as the requirements on the materials are continuously changing. Investigations at the Schering Institute focus on paper, polymers, elastomers, thermosets and reactive resin molding materials, modified with nanoparticles if necessary. The aging and durability determination of these solids as a function of thermal cycling and various mechanical and electrical stresses are being investigated to improve the reliability and longevity of the insulating materials. Voltage stresses are distinguished between impulse stress, high frequency impulse stress, AC and DC stress, and combined voltage stress, although extensive basic research is still needed to determine the influence of specific voltage stresses. In addition to voltage stresses, partial discharge measurements and the recording of dielectric parameters are also used to assess the quality of these insulating materials. New diagnostic methods are constantly being developed to enable the continuous recording of relevant data, which should lead to an improvement in the assessment and service life estimation.

Partial discharge measurement is of particular importance in high-voltage technology, as this method can be used to detect the smallest weak points in the insulation of high-voltage components. Research in this area continues to focus on new methods of detection, the evaluation of partial discharge signals and, in particular, the location of the partial discharge source, whereby extensive basic research is still necessary for partial discharge measurement technology under DC voltage stress, which must then also be incorporated into corresponding standards. The Schering-Institute is researching these topics intensively in close cooperation with industry and other colleges and universities. In addition to these classic areas, partial discharge diagnostics is also becoming increasingly important in the field of electromobility, so that here, too, investigations and developments are increasingly taking place in cooperation with automobile manufacturers.

In these fields of work, investigations are carried out on lightning protection systems with regard to current carrying capacity and current distribution. In particular, the interaction of metallic components and carbon fiber composites has been investigated for many years. Furthermore, the effects of lightning discharges on lines are analyzed as a function of their structure, location and coupling paths, and simulations of direct and indirect effects of a lightning discharge are carried out on components and model arrangements. A sensitive video system can also be used to detect sparks inside a model arrangement, allowing an evaluation of the various connecting elements in terms of their current carrying capacity and spark generation. The results can be used to improve lightning protection measures and to modify recommendations of lightning protection measures for future designs.