Application Of Static Var Compensators For Subsynchronous Resonance Suppression Simulation

Series capacitor compensation technology is a very economic and effective measure to improve transmission capacity and the system stability of the long-distance AC transmission systems. With the extended implementation of'West-East Power Ttransmission Project'in China, Point-to-grid transmission, with high-capacity steam turbine and generator units, relatively high compensation level of series capacitor, becomes a common mode. However, this kind of transmission mode is prone to lead to the sub-synchronous resonance (SSR) problem caused by the generator shaft damage, which may cause generator shaft torsional vibration and even destruction, thereby endanger the safe operation of power systems. Therefore, the SSR of the system research is of great practical significance and value of engineering applications.Considering the reality of a practical system with sub-synchronous resonance (SSR) problem, this article establishes the electromagnetic transient simulation platform of the system mainly based on PSCAD/EMTDC time domain simulation method. On this basis, by calculating the transient shaft torque of the system under a variety of working conditions and the impact of disturbances, analyse the possibility of SSR of the electrical system, study the electrical system and integrated damping characteristics. And taking three typical working conditions for example, according to the typical perturbation methods, and change of the shaft mechanical damping, capacity of Static Var Compensator (SVC), etc, respectively, calculate and analyse the SSO problem and the electromagnetic transient torques of the system. Finally, using the system eigenvalues method, theoretically analyse the system with or without SVC. And this article also has considered other methods, just as the parameters of SVC controller, the installation of voltage regulators and the use of modal separation method, for the SVC inhibit effect of SSR.