Research In Main Circuit Of STATCOM Based On IGCTs

Static Synchronous Compensator(STATCOM) can strengthen the stability of power system and enhance it's capability to transmit electricity, thus it has been widely studied and used all over the world. In recent years, the power system of our country is developing continously, it should have larger capacity and higher voltage. The capacity of STATCOM must be enlarged to be able to take effect, it is more pressing to do that.In this thesis, the main circuit of 6kV/200kVA STATCOM is lucubrated. The operation principle and the method of control of STATCOM is introduced. Many configurations used in high capacity STATCOM is analysed and compared. A new type power electronic switch named Integrated Gate Commute Thyristor(IGCT) is introduced in this thesis and the principle-electrics model of IGCT is established. To study the voltage balancing for IGCT series connection, voltage balancing circuit is designed and the dynamic course is simulated.As an remarkable scheme, cascade configuration is emphasized studied in this thesis. The mathematical model of the single phase three levels cascade STATCOM is established and the machanism of the voltage unbalance of capacitance voltages on DC side is carefully analysed. The main parameters of the cascade STATCOM based IGCTs are precisely designed. To verify the correctness of the designed production, simulation results are also present in this thesis.