Research On Optimization Strategy Of Microgrid Energy Management

With the rapid economic development in our country,the energy crisis and the environmental problem have become the problems that the country needs to focus on.In order to improve the environment conditions and reduce the dependence on fossil energy,the country vigorously advocates the development of green renewable energy.As an effective way for clean and renewable resources to connect with the grid,microgrid has drawn attention worldwide.Energy management is an important approach that optimizes and controls the controllable units to achieve goals like economic efficiency,stability,environmental protection and so on,under the guarantee of stable operation.Due to the large number of renewable resources access,microgrid faces the test of volatility and randomness of renewable energy.In order to improve the stability of microgrid operation and reduce the adverse impact of renewable energy,aiming at energy management strategy is of a great significance.Therefore,research on microgrid energy management in consideration of randomness is carried out as follows:Firstly,the operation characteristics of power generation units in microgrid are studied and the energy management models of power generation units are established,including the output power model of photovoltaic cells,diesel generators and gas turbines,the operation constraints of controllable power generation,battery charge and discharge model,the cost function and constraints.The load is based on the characteristics of its response to establish uncontrollable load,translational load and reduce load.The model of each part is as the basis for energy management strategy.Secondly,in order to improve the stability of the microgrid,aiming at the shortage of existing microgrid research,this thesis focus on two aspects of a microgrid energy management strategy based on two-stage robust optimization and energy management strategy for the isolated microgrid:One is to study a microgrid energy management strategy based on two-stage robust optimization.Because of the randomness and volatility of renewable energy output,in order to reduce its adverse impact on the microgrid,a microgrid energy management model based on two-stage robust optimization is established.The model uses the uncertainty set to describe the output of renewable energy and uses the uncertain budget to control the conservativeness of the model.The model is solved by the column and constraint generation algorithm and analyzes the impact of the uncertain budget on the operating cost by the example simulation.It is verified that the optimization strategy has better robustness and the superiority of the solution method.The other is to study the energy management strategy for the isolated microgrid.The isolated microgrid lacks the support of the grid,it has a higher requirement for the stability of the system.In view of the characteristics of isolated microgrid,the existing energy management strategy has been improved.The network loss is added to the objective function and the load satisfaction rate constraint is increased in day-ahead optimization.In the intra-day optimization,the three-phase unbalance constraint and the on-line reserve optimization constraint are added,which is beneficial to improve the power quality and power supply stability of microgrid.Finally,a simulation example is used to verify the effectiveness of the energy optimization management strategy and the utilization of renewable energy is improved.