ISBN 9783843954419

978-3-8439-5441-9, Reihe Energietechnik

Dirk Bösche
Investigation on the residual arc conductance in the mechanical part of Hybrid-Circuit-Breakers before and after current commutation

136 Seiten, Dissertation Technische Universität Braunschweig (2024), Softcover, A5

Zusammenfassung / Abstract

Significant amounts of energy is generated by the burning of fossil fuels. This causes the climate to change dramatically. To stop this, the use of renewable energy sources and the energy efficiency need to be increased. One attempt is to change industrial AC into DC grids. This has several advantages. Renewable sources and storage components can be implemented easily. In addition, energy otherwise lost during the production process can be retained. However, appropriate DC switches are needed to ensure a reliable and safe operation of those grids. Designing those switches is challenging. Mechanical switches perform exceptionally well in the on or off state. They provide low conduction losses and a galvanic separation. Transitioning from one state to the other can cause problems. Especially when small currents with alternating polarities should be interrupted. The opposite is true for semiconductor switches. Most of them can changing their state rapidly. But they cause significant conduction losses and are sensitive to overvoltages. To retain the advantages of both technologies, they were combined into one hybrid switch. In this thesis different hybrid switch topologies are clustered and evaluated. One example, its components and the switch-off process are explained. In this example an arc occurs during the switch-off process. It is extinguished by a semiconductor bypath, which has to stay on for a certain amount of time. This is necessary to allow the arc to subside. The on time is one decisive factor for dimensioning. Therefore, a test setup is designed to investigate the influence of contact distance and current value onto the arc decay process. A model is developed, which enables the reproduction of the arc resistance curve progression. In conjunction with determined approximation equations, model and measurement based results are compared. Finally, the results are summarized, challenged and some design considerations for an increase of the arc decay speed given.