Current cut-off device for high-voltage direct current with capacitive buffer circuit, and control method

A current cut-off device for high-voltage DC electrical current, comprising:

• a main line between a primary point and a secondary point;
• a mechanical primary switch and a mechanical secondary switch interposed successively in the main line between the primary point and the secondary point but on either side of an intermediate point of the main line, the two mechanical switches being each controlled between an open state and a closed state,
• a primary surge protector arranged in parallel with the primary switch between the primary point and the intermediate point,
• a secondary surge protector arranged electrically in parallel with the secondary switch,
• wherein the secondary surge protector is arranged electrically between the intermediate point and the secondary point, and in that the device includes, between the primary point and the secondary point, a capacitive buffer circuit, electrically in parallel with an assembly formed by the primary switch and the secondary switch, and electrically in parallel with an assembly formed by the primary surge protector and the secondary surge protector, the capacitive buffer circuit including an activation switch and a buffer capacitance.