Study Of Power System Stabilizer On Stability Of Synchronous Generator

Along with the development of the economic construction, the electric power industry of our country is developing quickly. The scale of the electric power system extends increasingly, the capacity that generate electricity the equipments also corresponds the aggrandizement, and the variety of the movement method of system is more and more multifarious. For guaranteeing the safety bitterly, the economy circulates and guarantees the electric power quantity, the electric power system circulate to the automatic control equip put forward a higher request.If PSS is not selected properly and settings are not configured appropriately as well as PSS locations, a series problem such as instability of operation and difficulty in regulation would be developed in operation. Therefore, making use of the advantage of PSS function, giving play to PSS control ability, combining the other measures to be taken, to improve the stability of power network becomes very important.In this paper the origination of the problem of power system stability and its principal mathematic analysis method are introduced, first. And the influence on the stability of power system by excitation system is discussed in detail based on dynamics model and theory of synchronous motor. The paper analyzed the reasons of negative-damping, using theory of small signal dynamic model and synchronous generator.Second, Dynamic Simulations on several PSS control strategies have been implemented and analyzed based on the mathematic anlysis. Excitation system and PSS system with different control strategy have been set up for single machine infinite bus system, respectively. Via changing PSS control strategy, comparations were made under small signal stability analysis and large disturbance stability. The simulation results show that the SGIB system with PSS2A recovery much more fast and more robust than any other systems.Finally, further validation of the control strategy has been performed via site PSS test at Zhejiang Guohua Yuyao Power station. The quick constringency of low frequency oscillation of generator which realized by new excitation stability strategy is of very positive significance for the safe operation of power system. Thermal accumulation of generator will be cut down through reducing swing times of generator, and at the same time, the stability of power system is improved. The subject is of potential both theoretically and practically. So it is necessary to carry out further study and evaluate on its application both theoretically and practically.