Research On Microgrid Modeling And Energy Optimization Strategy

Primary energy shortages,environmental pollution problems and growing demand for electricity are driving the development of high-quality electricity supply models.The potential for renewable energy is enormous compared to traditional methods of power generation,which are difficult to sustain,and distributed generation technology is the best way to ensure the efficient use of renewable energy.The microgrid is capable of aggregating multiple distributed generation units to serve as an extension of the grid for flexible power supply.On the one hand,it benefits from the use of local resources,which can improve resource utilization and reduce electricity costs,and on the other hand,it is subject to the intermittency and uncertainty of renewable energy.In order to use renewable energy more efficiently and maximize the benefits of microgrids,it is necessary to model the basic constituent units in microgrids and study energy optimization management strategies to resolve the above contradictions.This article firstly discusses the current status of energy in China,summarizes the development of microgrids at home and abroad,summarizes the research status of renewable energy output forecasting and load forecasting,microgrid modeling and control,and microgrid energy management in microgrids,finally explains the research significance of the selected topic in combination with the actual background.Then the working principle and mathematical model of common energy units in microgrid system are studied.Several common forecasting algorithms are introduced,and the load forecasting is taken as an example for research,and the forecasting results are compared and analyzed.Then,taking the small island microgrid as the research background,an island microgrid simulation model based on a heuristic control strategy is established.According to the fluctuation of renewable energy output,two different strategies are adopted with energy storage system as the core.By comparing and analyzing the operation status of the island microgrid in three different weathers: sunny,cloudy and rainy,it is verified that the simulation model can realize the autonomous operation of the island microgrid and ensure the optimization of energy to a certain extent.Since the heuristic control strategy cannot achieve global optimization,comprehensive consideration is given to the economics,operational reliability and environmental protection level of island microgrid operation,multiple evaluation indicators are given,a multi-objective optimization model is established,and two typical kinds of weather are analyzed by comparison.The operation status of the microgrid is verified to verify the feasibility of the optimization model.Finally,in order to study the real-time performance of microgrid optimization and ensure the optimal operation economy in the whole operation cycle,a bi-layer energy management model of grid connected microgrid is established.The upper layer is the day ahead optimization scheduling model,and the renewable energy output and electric load demand are obtained through short-term prediction.Considering the time-sharing price and two-way electricity trading,the output of each unit is calculated with the lowest system operation cost as the goal;the lower level is the day energy control model.Through the model predictive control,taking the output determined by the day ahead scheduling as a reference,combined with the ultra-shortterm prediction of the output and electric load demand of renewable energy,real-time rolling optimization is made to coordinate the efforts of all parties to correct the prediction error.Combined with the case analysis,it is verified that the bi-layer model can maintain the global optimization goal and adjust the operation of microgrid in real time.