Selectivity study for the Severstal site

The input data are contained in a single document which identifies the sources and their indices. Where necessary, assumptions have been made and justified.

Following this, the grid was modelled using dedicated software. After validation of the model by performance of a load flow study, the initial adjustments of the protective devices for the site were analyzed with the aim of identifying non-conforming cases (current-time curve analysis).

New adjustments guaranteeing the selectivity were then tested, proposed and integrated into an adjustment booklet.

Finally, a theoretical note on the principles of coordination of the protective devices in use on the site was compiled.

Through this study, the potential risks from protective devices failing to open in the event of a short-circuit, or from their importune opening, have been identified and eliminated.