Building And Application Of The Wide-Band Equivalent Models For Key Components In HVDC Converter Valve Systems

As the key devices of HVDC transmission system, converter valves should bear the overvoltage in different forms including switching, lightening and fast front overvoltage. The high frequency parasitic parameters and the distinction of the devices usually lead to a non-uniform voltage distribution in the converter valves and the wide band frequency electromagnetic noise is generated by periodical turn-on and turn-off processes of converter valves, which can impact communication and control systems. Building wide band equivalent circuit model is the foundation to solve above problems.So the appropriate wide band model, namely the integrated equivalent circuit model, is proposed to discuss wide band characteristics and parameter estimation of the devices in different physical structures on the base of the basic model in this paper. The validity is proved by comparing the fitting results and the test results from the HVDC test platform. Through the above modeling method, this paper combines with the subject "the physical field research of±10kV series IGBT converter valve systems" supported by the Smart Grid Institute. The focus is put on the wide-band equivalent model of the converter valve systems, based on which the over voltage distribution characteristics of the converter valve system and its influencing factors are studied. Combined with the distribution law of converter valve suffering overvoltage, over voltage distribution equilibrium measures are briefly discussed from the aspects of parasitic parameters, which has a certain reference value.