Studies On The Coordination Strategies Of The Renewable Generation Integration

The climate change and the shortage of energy has made the renewable energy the priority of many countries. The wind generation, photovoltaic generation and the electric vehicle are the three main renewable energy utilization methods and are under the fast development. Since the wind energy, solar energy have the intrinsic intermittence and fluctuation, their integration into the grid will lead to the power fluctuations. The traditional grid is designed for the centralized production, dispatch and distribution of electricity. When the share of renewable energy is small, the traditional generaion can compensate the power fluctuation of the renewable generation. However with the increasing scal of the renewable generation, the power fluctuation may go beyond the adjusting limitation, adding difficulties to the system operation and make the integration of renewable energy limited.Thus to the grid, the crucial issue of renewable energy integration is to maintain the balance between the generation and the demand. The wind power, solar power and the grid demand are all fluctuating and they add the complexity of the grid planning and operating. The objective of renewable energy is ro maintain the power balance with a acceptable cost and maxmimum the utilization of the renewable energy. The fundamental work is to assess the power fluctuation of the renwable energy, which tends to be overlooked in reality. Thus the renewable generation assessing model is necessary for the research of the sequential power fluctuation as well as the correlations among various areas. The planning and operating of grid need to be made on the system level, utilizing the correlations and complementarity between the various generations and load demands in order to limit the power fluctuation and reduce the investment in the reserve and transmission capacity.1) A method is proposed to assess the wind power fluctuation based on the NASA GEOS-5 DAS system. The wind power fluctuations in the 6 10-GW wind power bases are analyzed and the correlations between different wind bases are calculated. The method provides the basis for the regional wind power planning work.2) The charging models of Plug-in Electric Vehicle (PEV) are built under the free charging as well as under the low demand charging pattern. The impacts of PEVs on the grid demand is assessed. The synergistic dispatch of wind power and PEV charging is proposed. Through the analysis of the 4 wind-rich regional grids under 2020 scenario, the potential of PEV charging to absord the excess wind power in the night is illustrated. 3) Based on the correlation between the solar irradiation and the gird load fluctutions, the method of deploying the photovoltaic (PV) generation to follow the load demand is proposed in order to reduce the storage investment. It's proved that there is a strong correlation between the PV power and the grid load. Without the storage, the PV generation still has a remarkable integrating potential. The PV utilization rate is proposed. It's proved that the share of PV electricity can increase remarkably by reduce the utilization rate slightly while keeping the cost stable. 4) To the generation and network coordinating, according to the complex network model, the method is proposed to reduce the complexity by distinguish between the source and network. Following this methodology, the bi-level model for the integrated genetration and transmission maintenance is built. The character of the solution space is investigated to explain the "flat phenomenon". The partation searching method is proposed to improve the efficiency of the searching algorithm.