The Research And Design Of SVC Faced To Unbanlanced Load

As the increase of unbalance three-phase elements or loads, the power system's voltage unbalance becomes a threat against the security and economical operation of the power system. The TCR equipment has been proved to be an effective measure to reduce electric circuit loss, to increase working-system stable level, and to compensate the unbalance of the power system. But it has some shortcomings, such as low compensate efficiency, low response speed, and the restriction that the tranditional firing and monitoring system for thyristor valves could not satisfy the new requirements.Firstly, the negative-sequence and reactive power compensation which based on instantaneous reactive power theory was used to compensate every phase's power factor and improve the system's unbalance condition. Additionally, a method had been put forward to solve the over compensation problem. Secondly, the Static Var Compensator (SVC) based on Thyristor Controlled Reactor (TCR) which faced to the loads mainly uses open-loop control, this thesis put forward a control strategy based on local open-loop and global close-loop in the whole, which can improve control accuracy and assure response speed. Finally, In order to improve reliability, this thesis introduces the thyristor valves photoelectric firing and on-line monitoring system into the SVC design.The simulation by MATLAB/Simulink has proved that the control strategy which based on local open-loop and global close-loop in the whole put forword in this thesis can quickly compensate the system's Var and the load's imbalance. At last, the thesis put forword the design method of the software and hardware of the SVC.