The Capacitance Parameter Extraction & Experimental Research On Surge Characteristic Of UHVDC Converter Valve Tower

At present, High Voltage Direct Current (HVDC) is currently an important means for the world's major powers to solve the high voltage, large capacity, long-distance power transmission and power grid interconnection. With the increase of HVDC voltage levels, the problems of electromagnetic environment and overvoltage in converter stations increasingly dash forward show.For the overvoltage problem of Ultra High Voltage (UHV) converter system, supported by National Natural Science Foundation of China under grant No.50707008, the parasitic capacitance extraction of Ultra High Voltage Direct Current (UHVDC) converter valve tower and the voltage distribution characteristics were emphatically researched.Based on the boundary element method, a numerical method of parasitic capacitance for the multi-conductor system was studied, which can extract the parasitic capacitance parameter accurately and quickly in the premise of meeting the engineering requirements. For validity, simple models and capacitance testing experiments were designed, and both results have a good agreement. Besides, the method is applied to extract the parasitic Capacitance of Ultra High Voltage Direct Current (UHVDC) converter valve tower. In addition, in order to obtain the overvoltage distributions in the converter valves, the impact characteristic test of±800kV/4750A UHVDC converter valve tower was carried on, contained lightening and fast front overvoltage. Compared with the simulated computed result, some problem were appeared. By analyzing, testing suggestions were performed.