Vacuum technology for degassing of water-cooling system in high voltage direct current converter valve

A novel technique was developed to effectively degas the water cooling system, installed in the high voltage direct current (HVDC) valve. The low pressure, generated with a vertical water pump, in the dedicated bypass-tank significantly enhances evaporation of the various dissolved gases, and reduces their concentrations, oxygen concentration in particular, in the water cooling system. The degassing technique was physically modeled, analytically simulated, and experimentally tested. The measured results show that the vacuum technology considerably reduces the dissolved oxygen concentration in water to below 200×10-9. Moreover, the newly-developed degassing technique provides a total solution for improvemnt of security, reliability, and durability of the water cooling system, and the HVDC valve as well.