Control And Application Of Series Converter In The Unified Power Flow Controller

Nowadays, the development orientation of electric power system of all countries is that more and more transmission-line systems of electric power system is connected each other. UPFC is a kind of powerful and flexible power flow controller of FACTS. UPFC can control the active and reactive power flow in the line, and it can adjust the bus voltage. The series converter is the main power controller of UPFC.This paper discusses and establishes the stable voltage control model in the parallel side, and the cross coupling and the cross decoupling in the series side. With the simulation and experiment results, the paper verifies the power regulation results of the cross coupling and the cross decoupling. With the simulation and experiment results, the paper also verifies the other function of the series converter which is the dynamic voltage regulator and the simulation of line impedance.Fuzzy auto-tuning control is chosen in the cross coupling, which is aimed at increasing the speed of the cross coupling control, and this method can modify the PI factor at real time based on the error and the differential of error. With the simulation and experiment results, the paper can prove the usefulness of this method. Impedance tracking and fuzzy control are chose in the paper, which is aimed at improving the robustness of the cross decoupling. The impedance tracking can get the feedback value of outer power loop by real-time computing the line impedance, and the fuzzy auto-tuning control adopts the flexible proportional and integral in the PI controller of outer loop. With the simulation results, these two kinds of methods can be proved useful, the paper also compare the advantages and disadvantages of these two kinds of method.Our project team completes the static experiment of UPFC in the dynamic simulation laboratory where the single machine infinite bus system is built in. The circulation question of power flow is also discussed in the dual–circuit system. Restraining the system oscillation is another function of UPFC, and this paper analyzes it with the simulation results.