Research On Two-Time-Scale Energy Scheduling Strategy Of Microgrid

With the shortage of traditional fossil energy and the aggravation of environmental problems,microgrid with renewable energy as the main power supply mode has been widely concerned.As the main distributed energy sources in microgrid,photovoltaic and wind power show the characteristics of strong intermittence,volatility and uncertainty,which brings great challenges to the formulation of microgrid energy scheduling scheme.At the same time,in order to improve the dynamic scheduling ability of microgrid,this paper makes an in-depth study on the energy scheduling strategy of two time scale microgrid.(hour level and 15 minute level).due to the concentration decay grid energy management strategies in the large computational complexity,such problems as lack of flexibility,so based on the theory of multi-agent system,respectively,set up the system of wind turbines,photovoltaic units agents agency and variable load,energy storage system,each unit through the exchange of energy information between agents,to achieve the optimal operation of distributed system,which provides the theoretical foundation for subsequent research.The output characteristics of each micro power source in the microgrid are analyzed,and the influence of centralized and decentralized control architecture on Microgrid scheduling is compared.The important links between day ahead scheduling and day scheduling in energy management optimization scheduling are outlined,which lays a theoretical foundation for the research of energy scheduling strategy in two time scale microgrids.Aiming at the problem that the single-step scheduling of microgrid can not combine economy and operation stability,an optimal scheduling strategy based on two time scale microgrid energy management is proposed.The strategy takes the SOC state obtained by day ahead optimization as the given condition of day ahead optimization,which not only reduces the daily operation cost of microgrid,but also reduces the unbalanced power fluctuation of microgrid.A scheduling algorithm based on ADHDP algorithm is proposed.Based on the short-term forecast power,historical energy storage power and real-time electricity price information of each micro power source,the optimal output power of the energy storage system is optimized with the objective of minimizing the daily operation cost,and the intra day constraint interval is established with the day ahead ± 5% SOC fluctuation,which provides the SOC reference range for the intra day scheduling strategy.Case study shows that the proposed day ahead energy scheduling strategy can effectively reduce the daily operation cost of microgrid.Aiming at the problem that the single-step scheduling of microgrid can not combine economy and operation stability,an optimal scheduling strategy based on two time scale microgrid energy management is proposed.The strategy takes the SOC state obtained by day ahead optimization as the given condition of day ahead optimization,which not only reduces the daily operation cost of microgrid,but also reduces the unbalanced power fluctuation of microgrid.A scheduling strategy based on ADHDP algorithm is proposed.According to the short-term forecast data,historical energy storage power and real-time price information of each distributed generation unit,the optimal control variables of the energy storage system are optimized to minimize the daily operation cost,and the SOC operation reference interval is obtained.The intra day constraint interval is established based on the day ahead ± 5% SOC fluctuation,which provides the SOC reference range for the intra day dispatching strategy.Case analysis shows that the proposed day ahead energy scheduling strategy can effectively reduce the daily operation cost of microgrid compared with heuristic scheduling strategy.