Research OF Wind-thermal Power Joint Dispatching

The energy crisis and environment problem are increasing serious, so the development and utilization of renewable energy is getting more and more important. In recent years, wind power develops rapidly as the most promising renewable energy. But due to wind power’s volatility and randomness, the grid connection of large-scale wind power has caused many problems. Therefore, the research on description and compensation of wind power fluctuation is of great significant.Based on the discuss of the existing methods on compensation of wind power fluctuation, this thesis proposes a method that using thermal power and energy storage system compensate wind power fluctuation. It is named wind-thermal-storage joint system, aimed to let the output of the system reach a steady state.The thesis analyses wind power fluctuation characteristics from time domain and frequency domain. In time domain, it mainly research the distribution characteristics of wind power. In frequency domain, based on the principle of power spectral density, it reveals the frequency distribution of wind power and and demonstrates the convergence effect of wind power.Based on the principle of low pass filter, the energy storage system is studied for smoothing wind power fluctuations. The thesis puts forward the energy storage system control strategy of smoothing wind power fluctuations. The change of the low-pass filter cutoff frequency is analyzed for the effects of smoothing wind power fluctuations. And the calculation method of rated power and rated capacity for energy storage system is put forward.The thesis proposes a grid connection method that combined wind power, thermal power and storage energy; introduces the basic structure of the joint system, the simplified model of thermal power unit and the general structure of energy storage system. The smoothing strategy of wind power fluctuation is analyzed. Then the wind power is divided into low frequency part and high frequency part in frequency domain, based on the phase frequency characteristics of the thermal power unit. Wind power fluctuation in low frequency part is smoothed by thermal power and that in high frequency part is smoothed by energy storage system. The paper proposes the calculation method of thermal power unit quantity, analyzes the smoothing effect of thermal power on wind power fluctuation, then calculates the power and capacity of the energy storage system. Finally the output of joint system is obtained, and compared with the original wind power.