Summary: | DC high-speed circuit-breakers (HSCB) are the basic protection to cut off short-circuit and overload currents. People’s and railway infrastructure devices’ safety depend on their reliability and parameters. High-speed circuit-breakers, like any other electrical devices, display several electrical and mechanical characteristic parameters, which in many cases are interconnected. The article features these parameters of DC high-speed circuit-breakers that affect the operation safety of electric traction power supply systems. Moreover, it presents ways of their determination basing on laboratory and operational tests. Furthermore, requirements to be met directly and indirectly by DC high-speed circuit-breakers imposed by legal and standardization documents are described. Correlations between the breakers’ construction and their parameters are outlined. Basing on tests of leading European producers’ breakers, the article presents the impact of parameters of circuit where they are tested as regards HSCB parameters. It also deals with the problem of coordination of short-circuit protection and breaking currents of low values with respect to high-speed circuit-breakers used in Poland.
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