Capacity Optimization Of Micro-grid Hybird Energy Storage System

With the global energy crisis and environmental problems become increasingly serious,with photovoltaic power generation,wind power as the representative of the rapid development of distributed power generation.But because of the distributed power supply uncontrollable and random volatility,so that the integration between the large power grid there is a problem.Microgrid as a small controllable network,both can run the grid,you can also run on the island,for the distributed power supply access and management providing a convenient.However,the uncertainty of the distributed power supply has a great influence on the stability of the micro-grid.The introduction of the energy storage device in the micro-grid system can effectively stabilize the power fluctuation and improve the reliability and stability of the system.Due to the high cost of the energy storage device,it is urgent to solve the problem that the capacity of the micro-grid is limited,and the capacity of each part of the micro-grid is stable and coordinated.Aiming at the above problems,this paper has studied the scheme of optimizing the wind storage in the independent microgrid.The characteristics of photovoltaic,wind power and energy storage devices in microgrid are studied,and its output model is established.Based on the historical data,the vertical probability distribution of the distributed power output is obtained by using the longitudinal time probability analysis method.The sunrise force curve of the distributed power generation based on the longitudinal time probability is studied under different confidence levels.,Analyzes the characteristics of the distributed power supply available at different times and confidence levels.The capacity of the wind,light,and storage parts of the independent microgrid system and the coordinated operation between the power generation units have great influence on the stable operation of the system.For the independent micro-grid system,taking into account the wind and solar complementary features,different equipment life,installation,maintenance and replacement costs,combined with the sale of electricity and the national power generation subsidy policy to the annual load power shortage for power supply reliability constraints.Based on the scheme of the whole life cycle cost as the optimization target,the complementarity of the wind and light is quantified,and the optimization model of the independent microgrid wind and light storage capacity is established based on the actual installation site of microgrid and the distributed power supply.The capacity optimization software of the independent wind power storage system was prepared by MATLAB,and the correctness and validity of the improved scheme were verified by an example.Performance and cost of battery and super capacitor are different.Making full use of the complementary features of the two,according to the micro-grid system required energy storage capacity and storage capacity to match the two capacity,can effectively reduce the cost of energy storage systems,increase the lifetime and improve the reliability of micro-grid operation,economy.In this paper,the micro-grid hybrid energy storage two-stage optimal configuration configuration scheme,the first level using independent wind storage optimization software to calculate the system required energy storage capacity and storage capacity;secondary optimization through the opportunity constraints and genetic algorithm to determine the battery and super Capacitor capacity optimized configuration.The validity of the proposed scheme is verified by an example.