Fault Analysis and Simulation Test Research on Lightning Stroke-Caused Wire-Breakage of Overhead Ground Line

In important spanning sections of overhead transmission lines, once a serious accident such as tower collapse, wire breakage, or string loss occurs, it may have bad impact on grid security and public safety. In this paper, for the lightning stroke-caused wire-breakage fault of the overhead ground line, the discharge phenomenon of the helical backup wire clamp by lightning current is found for the first time. The cause of the wire-breakage is analyzed in depth and simulated lightning stroke test is carried out. The results show that the fault of the lightning stroke-caused wire-breakage is caused by violent discharge of the lightning current through the helical backup ground clamp. After the ground wire of the clamp is injured, it gradually breaks under stress concentration, then fall and contact with the A-phase conductor. The resulting power frequency short-circuit current causes the ground wire in the middle position to be melted again; there is obvious discharge phenomenon at the end of the helical wire clamp under the simulated lightning stroke, but the end contact of the wedge wire clamp is relatively good, which can reduce the hidden danger of lightning stroke discharge, and it is recommended to be used as backup wire clamp in frequent lightning stroke area.