Studies On AGC Mitigating Power/Frequency Fluctuation With Large Wind Farm Interconnection

As one of the most matured renewable energy technologies, wind power generation is facing with a great developing opportunity when the global environment concern and fossil energy shortage change traditional electric power industry from growth to quality. Different from conventional generators, wind power is an intermittent energy source, and its stochastic characteristic has a great impact on the traditional power system's operation. With the increasing penetration of the wind power in the power system, its impact is becoming more and more widespread. Currently, there are some noticeable characteristics of wind power integration behaving as following: the single wind farm has larger size; wind farms integrate at higher voltage level. In the power grid with higher wind power penetration, the voltage stability, transient stability and frequency stability are all influenced by the wind power integration. The frequency stability issues about large scale wind farm integration are investigated in this paper, the main contents of study are as followings:1. The dynamic mathematical model of wind power system is established for simulation and analysis, which consists of wind turbine, double fed induction generator, wind speed as prime power and dynamic electrical load. The dynamic model of double fed induction generator in the reference frame rotating in synchronous speed is given in this paper.2. The proposed model is realized by MATLAB/SIMULINK. Its validity and effectiveness is proved in four generators two areas power system, IEEE 30-bus testing system and the practical Shandong power system in 500kV voltage level. The results of the simulation demonstrate the effectiveness of the AGC.3. The dynamic simulation method is used to analyze the influences of wind power on the security and stability of system. Among the set values of wind power penetrations, the largest one without detrimental effects is regarded as wind power penetration limit. Furthermore, the wind power penetration limits of four generators two areas power system and IEEE 30-bus testing system are calculated.