Research on abnormal discharge of exhaust valve of HVDC converter valve

Abstract

The MMC converter valve adopts the water-cooled heat dissipation method. The automatic exhaust valve is installed at the upper part of the main water pipe, and the manual ball valve is installed between the automatic exhaust valve and the main water pipe, which is made of insulating material. During laboratory tests, it was found that the switch state of the manual ball valve may lead to an abnormal discharge of the manual ball valve. When the manual ball valve is closed, it is filled with air, and the insulating material bears high voltage, and the air inside will be broken down. This paper studies the abnormal discharge phenomenon of the manual ball valve, analyses the discharging principle, evaluates the influence on converter valve equipment, and proposes an optimal design scheme.