Research On Broadband Dynamic Simulation Model Of The Anode Saturable Reactor

In recent years,along with the rapid development of computer technology,power electronics and other related technologies,the HVDC technology has been rapid developed world-widely.Meanwhile,with the continuous expansion of China’s electric power system,"west power to east,mutual supply between north and south,nationw ide interconnection " has become an important strategy for the development of C hina’s power industry.Due to the unique advantages on long-distance transmission of the HVDC systerm,it has become an important part of C hina’s electric power industry.The most important component in the HVDC transmission system is the thyr istor valve.As the working condit ion of the converter valve is severe under normal operating condit ion,and the t hyr istor is fragile,the protective components of the thyr istor are very important.Among them,one of the key protective components is the anode saturable reactor.The anode saturable reactor can effectively inhib it the high change rate of current during the opening and closing process of thyristor to avoid the inrush current,so the saturable reactor plays an increasingly important role in the protection of thyr istor and HVDC system,and has become the indispensable part of the converter valve.At present,the key technology of the saturable reactor for valve,which is in a confidentia l state basically,is still in the hands of a few large internationa l equip ment manufacturers,and the research of our country in this area is lagging behind.In the research of the anode saturable reactor,the model research is the most important research topic considering its basic status,and a simple and practical broadband dyna mic model of the anode saturable reactor is urge ntly needed in engineering applications.In view of this,the establishment of broadband dynamic model of the anode saturable reactor is ma inly studied in this thesis.Starting from the basic knowledge of structure and electromagnetis m characteristics of the anode saturable reactor,a broadband dyna mic model of the anode saturable reactor with the core of only one single silicon steel is constructed.Based on this,a broadband dyna mic circuit model of the anode saturable reactor with mult ip le cores is established,and the model was verified by experiment.The ma in work is summarized as follows:1.The structure,arrange ment,electromagnetic characterist ics,the skin effect and core eddy current of the anode saturable reactor are expounded in detail,laying a foundation for the establishment of the model.2.Aiming at the proble m of low precis ion and practicability,the dyna mic model of the anode saturable reactor based on equivalent circuit method is proposed.The model takes into account the dynamic changes of the electromagnetic field inthe silicon steel sheet of the saturable reactor,and transfor ms the complicated calculation of electromagnetic field into a simple calculat ion of circuit.According to the model,the equiva lent model of any system involved anode saturable reactor can be deduced after the corresponding conversion.3.A method of fitting the inductance of the anode saturable reactor is proposed based on the dose-response curve.The inductance of the anode saturable reactor under excitation of any current can be obtained quickly.4.The 50 Hz frequency test and the high frequency test of anode saturable reactor are designed.By comparing the measured waveforms wit h the simulat ion waveforms from Matlab,the correctness and valid ity of the broadband dynamic model of the anode saturable reactor are verified.