Device for the electrical protection of power supply cables for permanent-magnet motors

A device for protecting against a short-circuit occurring on a high-voltage DC power supply line between a DC source and an active load, wherein the DC source includes a first contactor and a first fuse, and the device comprising an electrical distribution unit disposed between the DC source and the active load, the electrical distribution unit including a second contactor, the device further comprising a bypass circuit formed of a third contactor and a second fuse connected in series and set up parallel to the active load via lines independent from a high voltage DC power supply line, the bypass circuit configured to pass most of the current through the bypass circuit until a melting of the second fuse, and wherein the second fuse is of low rating corresponding to an amperage of less than 32 A, and the active load is a permanent-magnet electric motor of 30 kV W to 4.5 MW in power.