HEAF: Failure of the electronics in the switchgear cabinet as cause of fire

The international CSNI project HEAF investigates fires resulting from so-called High Energy Arcing Faults (HEAF). Arcing occurs when voltage differences between two electrically charged components are suddenly equalised. Arcing occurs, for example, when medium and high-voltage switches are opened and closed, which is why these switching operations must be carried out very quickly.

Arc faults are arcs that lead to damage or accidents. Since an arc can have a core temperature of around 10,000 degrees Celsius, there is a risk that the metal parts of the affected component (e.g. switchgear cabinet, transformer or cable) will evaporate explosively and possibly cause a fire.
 
For HEAF, a series of tests is being conducted on the high-energy failure of electrical components due to arc faults with possible subsequent fire. It is the US-American supervisory authority U.S. NRC that carries out the experiments, with the other project partners providing components or co-financing the experiments. In the first project phase, for example, Germany provided two high-voltage switchgears from a German nuclear power plant.

Currently, further tests with medium-voltage switchgear, which are to take place in 2019 and 2020, are being prepared within the framework of the next project phase. Germany provides eight switchgears of different voltage levels for these experiments.

GRS procured the switchgear cabinets and organized their dismantling at the nuclear power plant and the transport to America. Furthermore, in the second phase of HEAF, GRS will participate in the technical supervision of the tests and the in-depth evaluation of the test data on behalf of the Federal Environment Ministry. Despite the national phase-out of nuclear technology, the topic is interesting for Germany as the switchgear cabinets will be used for a longer period of time even after the shutdown of the plants, both in the post-operational phase and during dismantling. The results of the research project are incorporated into the evaluation and maintenance of and the further research into the safety of nuclear installations. In addition, the results can be used in many other industrial areas in which switchgear cabinets are used.