| Energy storage system(Energy Storage System,ESS)is an important means for rapid development and stable operation of the smart grid.In a modern society where the economy and science technology are booming and the demand for energy is rapidly increasing,energy storage equipment is not only a key factor in the utilization of renewable energy but also an effective measure to maintain the safe and stable operation of the power system.The development of energy storage equipment coincides with China's strategic thinking of adhering to the concept of green development,vigorously promoting the construction of ecological civilization and the "energy revolution".Energy storage equipment can be combined with distributed renewable energy(RDG)and load to form a microgrid(Micro-grid),which as a whole is planned,designed,operated,controlled and protected,relying on local energy supply to meet electricity Demand;that can also be connected to the distribution network to carry out "peak-cutting and valley-filling",change the traditional "ready-to-use" characteristics of the power industry,reduce "abandonment of wind and light",increase the consumption of renewable energy for the power system,Provide frequency support and voltage support to ensure the safe and stable operation of the system,and build a strong,stable,low-carbon clean,efficient and economic energy system.Energy storage equipment has a high investment and technical requirements at one time,so that energy storage equipment cannot currently join the grid on a large scale.Therefore,in order to give full play to the role of energy storage equipment,this paper systematically studied the problem of energy storage equipment location and capacity allocation optimization.The main contents of this thesis are as follows:1)Fully analyzed the characteristics of distributed renewable energy,energy storage equipment,and load.Especially to characterize the source-charge uncertainty from multiple time scales,and study the impact of distributed power and energy storage equipment on the two integrated microgrids and distribution network;their characteristics are analyzed separately to determine the effect of energy storage equipment on power quality and reducing system network losses.2)From the perspective of energy storage life,optimize the configuration of the energy storage capacity of a micro-grid with a high proportion of independent operation connected to renewable energy,and obtain the optimal solution with the smallest pollution emissions and the highest economy.In capacity planning,a two-layer optimization model has adopted: the outer optimization model is responsible for solving the investment problem of energy storage capacity planning of the microgrid system,and the inner layer model considers issues such as operating costs,energy storage life loss,and polluting gas emissions.Calculating the energy storage life using the rain flow counting method can fully consider the factors that affect the life of the energy storage equipment;the particle swarm double-layer optimization algorithm is used to optimize the energy storage capacity of the microgrid,and the calculation results verify the feasibility of this method.Finally,comparing the two calculation methods of fixed life and precise life,and the two optimization methods of comparing the lowest emission mode and the life optimization mode,it provides effective suggestions for the energy storage capacity configuration and operation mode of the microgrid.3)Starting from the weak link of the distribution network,when configuring the location and capacity of the energy storage device of the distribution network,the voltage offset of the grid node,the net loss and the economy of the energy storage device is also taken into account.Combining the differences in source-charge uncertainty at different time scales.Solving at the outer layer requires a long-term energy storage investment planning model with energy storage equipment energy balance as the constraint and considering source-charge stochastic uncertainty.The inner layer solution needs to be based on the condition of the power balance of the energy storage equipment,consider inner model: source-charge forecast error uncertainty and short time scale optimized operation of the distribution network.After that,the compound differential evolution algorithm is used to solve the built model to obtain the location and capacity configuration of the energy storage device.Finally,the simulation and analysis of the actual calculation model prove the effectiveness of the model and algorithm. |
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