Research Of Power System Transient Stability Preventive Control With UPFC

Power system transient stability preventive control and optimal problem has combined the stability and economics of power system together. FACTS can control the parameter and structure of the AC power system flexibly and fleetly, then the system stability and reliably can be improved greatly, Unified Power Flow Controller (UPFC) colligates the control function of many FACTS element, and has been considered as the most creative and powerful element in FACTS. So, the influence of UPFC in power system transient stability and transient stability preventive control has been researched in this paper.Firstly, the transient stability analysis method: the Time-dominate method and the direct method is introduced, the basis concept of transient stability control and the method of preventive control and emergence control is also introduced.Secondly, the method and realization of power flow calculation with UPFC is introduced, and the simulation is carried out. Then the model of implicit trapezoid time-dominate simulation method with UPFC is established, and also give two scheme of the UPFC controller, the two scheme is compared during the simulation calculation, and draw the conclusion that UPFC both has advantage and disadvantage in improving power system transient stability.Thirdly, the model of Optimal Power Flow (OPF) with UPFC is established, and solved by interior point method. By the calculation, draw the conclusion that the fuel cost is higher when the system with UPFC, and the control aim and location of UPFC influences the fuel cost calculated by OPF.Lastly, the model of Transient Stability Constrained OPF (TSCOPF) with UPFC is established, and also solved by interior point method. By the calculation, draw the conclusion that the stability of the power system is enhanced after install the UPFC, and also make the fuel cost of preventive control decreased, so improve the power system economics.