Gas-filled spark gap with high follow current extinction capacity

A gas-filled spark gap (2, 102) for the protection of an electrical installation, including:

• a casing (4, 104) delimiting an internal space (5), the casing (4, 104) being gastight;
• two elongate electrodes (13, 113, 14, 114) along a propagation trajectory (T) and housed in the internal space (5), the two electrodes (13, 113, 14, 114) delimiting between them an inter-electrode space, the two electrodes (13, 113, 14, 114) being arranged in such a manner that the inter-electrode space includes successively along the propagation trajectory (T) a striking chamber (17) situated between first portions (18, 19) of the two electrodes (13, 113, 14, 114) to strike an electrical arc between the first portions (18, 19) of the two electrodes (13, 113, 14, 114) and an arc-extinguishing chamber (20) situated between second portions (21, 22) of the two electrodes (13, 113, 14, 114) to extinguish the electrical arc, an isolation distance (di) being defined as a shortest distance between the two electrodes (13, 113, 14, 114) in a plane transverse to said propagation trajectory (T), the isolation distance (di) between the second portions (21, 22) of the two electrodes (13, 113, 14, 114) being greater than the isolation distance (di) between the first portions (18, 19) of the two electrodes (13, 113, 14, 114), said arc-extinguishing chamber (20) including mutually spaced divider plates (29, 129) distributed between the second portions (21, 22) of the two electrodes (13, 113, 14, 114);
• two connecting terminals (11, 111, 12, 112) accessible from outside the casing (4, 104) and intended to enable electrical connection of said gas-filled spark gap (2, 102) to the electrical installation, the two connecting terminals (11, 111, 12, 112) being respectively electrically connected to said two electrodes (13, 113, 14, 114);
• and
• an inert gas trapped in the internal space (5) of the casing (4, 104).