Device and method for disconnecting a high-voltage direct electric current with a fuse, and oscillating-current overload system

A device for disconnecting a high-voltage direct electric current, the device including:

• a main circuit, in which circulates, in a conducting configuration of the disconnecting device, an operational electric current at a direct-current nominal operating high voltage (Unom) of the device;
• at least one disconnecting module, interposed in the main circuit between a first point and a second point of the main circuit for the disconnecting module, the disconnecting module comprising a main branch, between the first point and the second point of the disconnecting module, with at least one fuse interposed in the main branch between the first point and the second point, the operational electric current circulating, in a conducting configuration of the disconnecting device, in the main branch,
• and the disconnecting device being of the type in which the disconnecting module comprises an overload system which, in an overload configuration of the device, in the presence of a fault current in the main circuit, is able to generate an overload current to ensure the melting of the fuse,
• wherein the overload current is an oscillating current which, in the main branch, over at least one half-period of oscillation, is added to the fault current in terms of absolute value to ensure the melting of the fuse.