OVERVOLTAGE PROTECTION DEVICE AND PROTECTION METHOD FOR DIRECT CURRENT SIDE OF FLEXIBLE DIRECT CURRENT TRANSMISSION SYSTEM

摘要

An overvoltage protection device and protection method for a direct current side of a flexible direct current transmission system. The protection device (7) is connected to a positive electrode and a negative electrode of a direct current line (8) in parallel, and is used for conducting an action to draw away a fault current when the direct current line (8)is overvoltage because of an alternating current line I (4) or the direct current line (8) has failed or when a valve base controller detects that a short circuit fault has occurred at any electrode of the direct current line (8) has occurred, thereby restraining the overvoltage level of the direct current line (8) and protecting a valve body (9) of a converter valve. The protection device (7) uses an overvoltage or mandatory breakdown element for improving the overvoltage protection performance, thereby solving the problem of overvoltage caused by the fault of the flexible direct current transmission system.