| With the rapid growth of the electricity demand, power systems tending to interconnect between regional power grid, and the stability is a key factor that influences the interconnection between bulk power grids. The increase of wind power penetration brings serious challenge on the safe operation of power system. Therefore, it is an urgent task to study the stability of the grid integrated with large-scale wind power. The main contents and contributions of the paper are as follows:The mechanical models which mainly including aerodynamic, pitch angle control system and the shafting of wind turbine are studied. The equation of state under the synchronization reference frame of the doubly-fed asynchronous wind generator (DFIG) was derived and the mathematical model of frequency converter and its control system was built.Based on the detailed model above, the single doubly-fed induction wind turbines infinite simple wind power system model is established and linearized state equation of small interfering above simple wind power system stability analysis is derived. Then the analysis gives an impact on the low-frequency oscillation mode of the relevant state variables; Then the small signal stability and transient stability of double-fed wind turbine integrated three machines nine node system is analyzed and its mechanism are described.The impact of wind farm network capacity, transmission distance and tie-line power on the small signal stability and low frequency oscillation of interconnected system with DFIG wind farm is studied. With the increase of transportation distance of wind power, the damping ratio of the system is worsened of which the interarea oscillation mode is affected more obviously; with the increase of tie-line power, the frequency and damping ratio of inter-area oscillation increase and then decrease. It can be seen that, the impact of wind farm on each oscillation modes should be considered when determining the wind farm site. |
PDF Full Text Request