LCC analysis of different resonant circuits and solid-state circuit breakers for medium-voltage grids

The increasing usage of distributed power generation, leads to an increased short-circuit power in medium voltage grids. As a consequence, new concepts for limiting short-circuit currents are required. One possible solution is based on resonant circuits. These circuits are able to limit short-circuit currents fast, at preset levels. Four different circuits will be presented and compared with regard to technical aspects. In order to integrate new technologies into present power systems, costs are a decisive factor. In this paper, a complete Life Cycle Cost (LCC) analysis is carried out. It will be shown that, the design of resonant circuits offers some degree of freedom, which gives the opportunity to design circuits at minimal costs. The optimized solution strongly depends on the economical life time, which is assumed to be 10 or 20 years in present power systems. Finally, these costs are compared with solid-state circuit breakers, which are able to turn-off a short-circuit within a few 100 mu s.