Impact Of Large Scale Wind Farm Integration On Power System Transient Stability

With the increase in wind power capacity and wind power the proportion of power increase, various problem about wind-related power system stability and operation is becoming increasingly apparent. In particular our country make a large base and large scale wind power grid development plan, wind farms access to high voltage rated increasingly, the output power fluctuation and intermittent impact on the system will be more and more obvious, making the wind farm for power systems continue to grow.In response to large-scale wind power access, to ensure that wind power system operation after access to the reliability, security and stability of wind power, especially large-scale wind power on power system has an important impact theoretical and practical value. This paper analyzes impact of large scale wind farm integration on power system transient stability, the main contents include:First of all, the overall model configuration of fixed speed induction generator (FSIG) and directly driven wind turbine with permanent magnet synchronous generator (D-PMSG) are presented, respectively. The aerodynamic model, shaft system model of wind turbines are presented; the paper derives the dynamic model of the normal asynchronous generator and permanent magnet synchronous generator expressed in the reference frame rotating in synchronous speed; focus on establishing the model of PMSG converter.Secondly, the paper analyzes the dynamic characteristics of different wind turbines under fault in power network. Based on the dynamic characteristics of induction generator, the paper introduces the use of SVC to improve its transient stability; the decoupled control principle and control model of converter of D-PMSG are studied, in order to improve the low voltage ride-through (LVRT) of D-PMSG.Again, the paper analyzes the single type wind farms by the composition of different types of wind turbines for power system transient stability. In the analysis of FSIG wind farms, taking into account three-phase short circuit fault and wind farms installed the SVC; in the analysis of D-PMSG wind farms, the simulation of the two situations, using grid side converter to implement reactive power compensation, is respectively conducted under fault in power network.Finally, the paper analyzes the power system transient stability, after hybrid wind farms accessing, comprising FSIG along with D-PMSG. An improved coordination of reactive power control strategy for D-PMSG is used, to take full advantage of its ability to meet the reactive power to support the wind farm demand, and to improve the performance of wind power and reduce the cost.