Analysis And Suppression Study Of Subsynchronous Resonance In Power Systems

Large-capacity and long-distance transmission is the necessary demand of the electric industry development of our country, series compensation is a effective way to enhance the long-distance transmission ability and the stability of the system. However, if the resonant frequency of series compensated transmission network and the natural frequency of turbine-generator shaft complement each other (the sum is equal to synchronous frequency), it may result in Subsynchronous Resonance (SSR). This thesis is focused on SSR caused by series compensated capacitance. The main work is about the follows:(1) Two SSR analysis methods of multi-machine power systems are studied, which are based on the famous electromagnetic transient simulation software PSCAD/EMTDC: the complex torque coefficient method realized by time domain simulation-the test signal method,and the time domain simulation method. Then, the complex torque coefficient method realized by time domain simulation-the test signal method's applicability for the SSR analysis of multi-machine systems are introduced aimed at different conditions: identical and equal load, identical but unequal load, and no-identical multi-machines systems, and the advantages and disadvantages of this method are analyzed and contrasted with the time domain simulation method, this study could provide a reference for the SSR analysis of multi-machine systems based on simulation software.