Research For Modeling And Application Of STATCOM, SSSC, UPFC

Along with the development of modern power system to enter a new stage of the large-scale system, ultrahigh voltage and long-distance transmission and interconnected power network, as well as the gradual improvement of the electricity market and the commercialization of power enterprises, power system needs more and more control means to regulate the power flow and improve stability. Flexible AC Transmission (FACTS) is a solution to the challenges. However, FACTS technology offers many new features and changes of power system operation and control. Therefore, It has important meaning of power system analysis program for the study of FACTS technology and the establishment of adaptable and accurate simulation model.The thesis carry out exploration and research on simulation model of FACTS devices which are based on voltage source converter(VSC)—STATCOM, SSSC and UPFC. By referring to lots of documents, the thesis discusses the basic principles and application of STATCOM, SSSC, UPFC, especially the working principle and technology of VSC. Based on the analysis of principles and application on STATCOM, SSSC and UPFC, the static models are determined which is compatible with the original power flow program, the new quasi-steady model is proposed which take dynamic process of DC capacitor in consideration. These models are achieved on PSD-BPA Transient Stability Program which is developed by CEPPI Power System Department and the application scope of these models is determined through the simulation results. Further more, According to the problem of UPFC control strategy of constant line-power,three new control strategies are suggested--constant interface power flow,stepwise control and PSS control--for giving full play to the function of UPFC and can make contribution to system application.