Study On Power System Forced Oscillation And Suppression With Wind Power Integration

Power oscillation has become an important factor in affecting the dynamic stability and the transmission capacity of modern interconnected power system. On the one hand, tie-line power oscillation occurs frequently despite that system damping is positive in recent years. And forced oscillation which is proposed based on resonance mechanism can be a good explanation of such power oscillation performance. On the other hand, wind power, as one of the most potential renewable energies, has entered into a rapid development stage. However, wind power fluctuation brings power system disturbance and leads to power system forced oscillation. Therefore, studying on power system forced oscillation with wind power integration has been a major task.This paper studies several key questions such as reasons of wind power forming forced oscillation source, mechanism as well as suppression of forced oscillation with wind power integration and so on. Main achievements and conclusions are as follows:Firstly, the power system mathematical model with doubly fed induction generators is established, which is used to analyze forced oscillation with wind power integration. Then, the forced oscillation mechanism of single-machine infinite system(SMIB) is deduced. The influence of generator inertia time constant, generator damping coefficient, and system impedance on forced oscillation are studied as well. After that, the accuracy of theoretical analysis is verified by time domain simulation.Secondly, considering wind shear and tower shadow effects, a wind turbine mathematical model is presented. After analyzing relationships among equivalent wind speed, mechanical power and electromagnetic power, the reason of wind power forming forced oscillation source is gained, which is wind power fluctuation frequency is consistent with power system natural oscillation frequency. After that, the accuracy of analysis is also verified by examples of power system with wind power integration.Finally, power system forced oscillation suppression is collated and analyzed. And the power system stabilizer is designed, which is economical and easy to implement. The designed stabilizer can improve power system damping characteristics and suppress forced oscillation effectively.