APPARATUS FOR SUPPRESSING OVERVOLTAGE IN SINGLE POINT BOUNDED SECTION OF UNDERGROUND TRANSMISSION SYSTEM

摘要

The present invention relates to a device for reducing overvoltage in a single point bonded section of an underground transmission system comprising a detection unit and a bypass switch. The detection unit is connected to a sheath voltage limiter in parallel and detects current flowing between the sheaths of the transmission line. The sheath voltage limiter is installed in a single point bonded section of a transmission line. The bypass switch operates when the current flowing between the sheaths is over a reference value and forms a return path of fault current. The present invention is provided to secure the return path of the fault current in the single point bonded section of the underground transmission system by using the excitation feature of a driving coil, thereby effectively restricting the overvoltage generated in the single point bonded section and minimizing transmission loss when normally operated according to the impedance features of the driving coil.