Research On TCSC Control Schemes For Damping Teh Low Frequency Oscillation Of Power Systems

The Thyristor Controlled Series Compensation (TCSC) is an important controller among the flexible AC transmission system (FACTS). By adjusting the trigger angle of thyristor, TCSC can regulate the reactance from capacitive to inductive mode continuously. Thus, the power flow is controllable and the low- frequency oscillation is damped. Also, the system stability is enhanced. Some issues about TCSC to damp low-frequency oscillation are mainly studied in this paper. The primary coverage is as follows: Using topological model building method, the TCSC steady state model is set up. By analyzing the relationship between the thyristor trigger angle and fundamental impedance, and the relationship between the trigger angle and fundamental and harmonic components of capacitive voltage and inductive current, the TCSC parameters of planning Yi-Feng project are explored. From the extended Phillips-Heffron model of single machine infinite bus system with TCSC established in this paper, the form and properties of damping torque provided by TCSC is analyzed, and the condition of providing positive damping torque is proposed, also the selecting principle of TCSC controller parameters is proposed. Simulation results in time domain prove the viewpoint presented in this paper. A new scheme of adaptive fuzzy damping controller of TCSC, based on adjusting control rules and output scaling factor, is proposed. Simulation results in time domain prove the proposed adaptive fuzzy damping controller is robust under various disturbances and operating modes. By establishing the linear model of multi-machine power systems with TCSC, their eigenvalue analysis method is proposed. The low frequency oscillation mode and the optimal location of TCSC can be determined by eigenvalue, eigen-vectors, correlation factor, and proportion of mechanism-electricity. The analysis software of multi-machine power systems with TCSC in frequency domain has been formed. The design method of TCSC fuzzy variable structure damping controller (FVSC) in multi-machine power systems is presented. With the adoption of fuzzy approaching method, the control system is robust under the parameter perturbation and disturbance mode. At the same time, the igh frequency flutter?is avoided. Simulation results in time domain prove the proposed FVSC control is robust under various disturbances and operating modes. Simulation results in time domain under the large disturbance show that the presented TCSC adaptive fuzzy control and FVSC has good effects on the oscillation after the large disturbance, and could enhance the system transient stability. On the basis of the research results in this paper, some excellent conclusions are obtained.