Damping Control Research Of The Area-unit By SVC

Static Var Compensation (SVC) is one of the flexible AC transmission system (FACTS) which has been applied since 1970's. By adjusting the trigger angle of thyristor , SVC can regulate the reactance from capacitive to inductive mode continuously. Thus, it can control the voltage of the power system, damp the low frequency oscillation and enhance the system stability, and so on. Some issues about SVC to damp low-frequency oscillation are mainly studied in this paper. The primary coverage is as follows:Based on the concept of power-terminal, the model of unit-power terminal is set up and its oscillation modes are analyzed in this paper. Thus, the identification method of off-line oscillation modes of unit is introduced and the damping-control method of the area-unit by SVC is advanced.Aiming at the unit-power terminal model and based on the principle of improving damping characteristic of power system by SVC, this paper proves that the best location of SVC damping control is the electrical center of power system. From the extended model of unit-power terminal with SVC, this paper analyzes the forms and characteristics of damping torque provided by SVC, and proposes the condition of providing positive damping torque and the selecting principle of SVC controller parameters.Based on the SVC model given by BPA program, and using the BPA program and PRONY identification method, this paper simulates the China southern power grid whose power terminal is the hengsheng-chuandong-yuping in the northeastern power grid of Guizhou. The simulation results in time domain show that SVC can effectively damp low-frequency oscillation of power system if the SVC controller is set up according to the way given by this paper.