Secondary arc in hybrid AC DC overhead lines

This presentation covers a specific issue related to hybrid AC / DC overhead transmission lines: the extinction of the secondary arc current of a faulted DC pole. As a result of a pole-to-ground fault, breaker openings interrupt the short-circuit current. Because of the inductive and capacitive coupling between the AC circuit and the faulted pole, a small AC current (a few 10ths Amps) keeps flowing in the fault. This current is known as the secondary arc current and it may disappear after some time.