The rotor shaft of a steam turbine generator consists of several masses, such as rotors of turbine sections, generator section and exciter section. When the generator is perturbed, it will cause torsional oscillation between different sections. In long-distance high-capacity transmission lines, series compensation with capacitors can enhance power transfer capability of power system, however it may cause subsynchronous resonance (SSR) between the turbine shaft and serial compensation., which produce large shaft torques can result in a reduction in the shaft fatigue life and possibly shaft failure, threatening the security of generator unit and stability of power system. In China the 1000kV HVAC transmission line with series compensation has been put in operation since 2009. Near the Nanyang substation, there has a power plant in Henan power grid. So it is necessary to model the power plant and HVAC transmission line to simulate the possibility of SSR problem. Based on the power system simulation software ADPSS developed by China Electric Power Research Institute (CEPRI), this paper built up the simulation model using the electromechanical-electromagnetic transient hybrid method, and simulated the SSR possibility between the power plant and HVAC transmission line series compensation. The simulation results showed that with the generator parameters given, there has no risk of SSR between them. This paper also gives an evaluation principle of generator SSR risk when connected into a power grid.
Series Compensation of Transmission Systems: A Literature Survey