An energy supply with direct current (DC) offers enormous savings potential in the context of the energy transition, especially in industry. By using DC grids, the conversion of AC voltage into DC voltage can be dispensed with for many technical applications, regenerative energy generation plants can be directly integrated into the energy supply, energy losses can be minimized, and energy flows can be bidirectionally controlled/regulated.
In his keynote at the 4th Relay User Forumon 25 and 26 October 2021 at the VCC in Würzburg, Professor Frank Berger, Head of Electrical Apparatus and Switchgear Group at TU Ilmenau, gives an outlook on how future DC switching elements will solve switching tasks.
About the lecture:
Electrical networks are increasingly evolving towards a DC system. The widespread use of DC networks in the low-voltage range poses new challenges for switchgear and components.
Some optimization topics for classical DC switchgear are well known, such as the improvement of arc quenching phenomena or contact and insulating materials. However, it is also important to consider that these switching devices are increasingly being used in hybrid switches.
This poses new challenges for the mechanical switching element: on the one hand, the contact material is subjected to high stress, and on the other hand, the extremely short arc extinction time during the switch-off process is problematic. Both requirements necessitate new physical properties of the contact materials and new design principles for circuit breakers.
Another important aspect is the development of special power electronic switching elements that can completely replace the mechanical switch under certain conditions. The increased use of power electronic switching elements, in combination with and without electromechanical switchgear, will in future make it possible to implement improved measuring and diagnostic functions in the switchgear and in the DC networks. This will allow protection functions to be carried out quickly and specifically, and even power flows within the low-voltage network to be regulated.
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