Award-winning master's thesis on innovative switchgear concept

At this year's 58th OVE Energy Technology Conference in Linz, M. Sc. Arno Bernhardt presented a highly regarded energy-efficient switchgear concept. He had analysed and described the innovative concept in concrete terms as part of his master's thesis "Modelling, simulation and design of a hybrid DC low-voltage circuit breaker".

TU Ilmenau
Arno Bernhardt presented the research results achieved in his master's thesis at the OVE Energy Technology Conference.

As a result of the steady progress of the energy turnaround and the associated increasing decentralization of the generation structure of electrical energy, locations of electricity demand and locations of electricity generation are coinciding more and more frequently. This opens up many opportunities to use new concepts in the field of electrical energy supply. One example of this is local stand-alone grids at building or neighbourhood level, also known as microgrids. Together with the use of renewable energy sources such as photovoltaic systems, they enable a certain independence from the public power grid. At the same time, the direct use of the direct current provided by renewable energy plants and the resulting significantly shorter transmission distances also offer significant potential for improving the efficiency of the electrical energy supply.

The basic prerequisite for exploiting these advantages is high-performance DC switchgear. At the same time, these should be capable of assuming protective functions for persons and systems. Conventional mechanical switchgear, as currently used throughout the country, is not suitable for the requirements associated with direct current.

Innovative approach implemented in practice

Experts consider the concept of the hybrid switch to be a promising approach for a high-performance DC switchgear. This concept combines two basic switching device technologies: mechanical switching and power electronic switching. This ensures that electrical energy can be transmitted with extremely low losses and, if necessary, that this transmission can be interrupted just as safely, quickly and reliably.

In his master's thesis at the Group of Electrical Devices and Systems, which was supervised by the group head Prof. Frank Berger, Arno Bernhardt dealt with the structure, function and modeling of such a hybrid switch. He identified central components of the hybrid switch, such as its control circuit. This circuit is the basic component of the hybrid switch and was developed as part of the thesis. The central process for the hybrid concept is the so-called commutation process. This process describes the transfer of the current from the mechanical switching device to the power electronic switching device. Without the successful completion of this process, the concept of the hybrid switch cannot unfold its effect. Accordingly, in the course of his work, Arno Bernhardt developed a commutation model which is as simple as possible and which can be used to investigate fundamental relationships of the commutation process.

Due to the high quality and relevance of his research results for innovative energy supply systems, Arno Bernhardt was honoured with the Professor Werner Rieder Award at the OVE Energy Technology Conference 2021. The OVE Austrian Electrotechnical Association networks companies and institutions as well as experts and interested parties from the entire field of electrical engineering. Every year, the association holds its power engineering conference at different locations. In 2021, the conference focused on environmentally friendly technologies for power supply. High-ranking experts from industry, energy companies and grid operators as well as from research and politics discussed and presented innovative developments and concepts in the field of electrical energy supply.