| With the depletion of traditional energy and the emergence of environmental problems,the development and utilization of renewable energy has gradually attracted more and more attention.However,the intermittence and uncertainty of renewable energy seriously hinder its extensive development and utilization.As a new technology,microgrid(MG)can effectively integrate renewable energy and realize the optimal allocation of resources by using its flexible and diversified internal structure and control mode,which has become an important part of effective power supply.At the same time,with the increasing number of microgrids in local areas,independent microgrids with the same interests or goals are more likely to form a cooperative alliance as a reginal interconnected microgrid system(RIMS).By adopting the form of regional interconnection,the microgrid group can make more effective use of the complementary characteristics of renewable power and load difference among sub microgrids in the system to carry out mutual support of power supply,improve the reliability and economy of users' electricity consumption,and realize the cooperation and mutual assistance among the sub microgrid in the interconnected system,which is one of the important research directions for the development of smart grid in the future.From this point of view,this paper studies and analyzes the positive role of mutual power support mechanism in the economic optimization of regional interconnected microgrid system.The main innovations and research results are as follows:(1)The prediction of renewable energy is studied to build the foundation for the economic optimization of regional interconnected microgrid system.Based on data preprocessing technology and dynamic adaptive variable weight optimization theory,a combined forecasting model of renewable energy is established.The prediction model proposed in this paper is constructed by using the ensemble empirical modal decomposition(EEMD),autoregressive integrated moving average model(ARIMA),long short term memory(LSTM),general regression neural network(GRNN)and brain storm optimization(BSO).Make full use of the advantages of each sub-model in dealing with specific data types to predict the renewable energy data series.Taking the wind speed prediction with strong volatility as an example,the historical data of wind speed is taken as the input variable of the prediction model,and the future wind speed data is taken as the output of the prediction model to study the case verification.The results of case studies show that the prediction model proposed in this paper has better accuracy and generalization ability compared with other reference prediction models.(2)Capacity optimization of the reginal interconnected microgrid system is studied.By fully considering the randomness,fluctuation of renewable energy and load difference,the life cycle cost optimization of regional interconnected micro-grid system is taken as the objective function.Under the premise of meeting the reliability of power consumption and related constraints,genetic algorithm is used to integrate the mutual power support mechanism into the process of system capacity optimization,fully considering the impact of power dispatching frequency on the life of energy storage system,so as to optimize the optimal installed capacity of renewable energy power generation and energy storage batteries in the regional interconnected system.A case study of the regional interconnected dual microgrid system in remote area is carried out for a year.The results show that by considering the power exchange among the sub microgrids in the optimization of the system capacity,the overall economic performance of the system can be effectively improved,and the unnecessary installed capacity of the renewable power generation and energy storage battery in the system can be reduced.In addition,by introducing a reasonable power transaction price,the benefits obtained by adopting the regional interconnection mode can be more equally distributed among sub microgrids,thus enhancing the willingness of the sub microgrids to adopt the regional interconnection mode.(3)The power dispatching optimization of regional interconnected microgrid system is studied.Considering the active role of power interaction among sub microgrids in daily dispatching optimization of regional interconnected microgrid system,and combining with the supply state of renewable energy and the demand state of load in the system,a competitive transaction price of renewable power among sub microgrids in the system is established according to the principle of interaction between quantity and price to realize the economic optimization of power dispatching of the system.A regional interconnected microgrid system including three sub microgrids is selected as the case study and analyzed.By making a phased dispatching optimization strategy,the minimum operation dispatching cost of the regional interconnected microgrid system is taken as the objective function for optimization.The results show that by fully considering the power interaction mechanism in the interconnected system for dispatching optimization,it can effectively reduce the operating cost of the system and the emissions of carbon dioxide and polluting gases,improve the local consumption of renewable energy,which shows good economic and environmental benefits.In addition,by using the renewable energy power among the sub microgrids to support each other,the independence and anti-interference ability of the regional interconnected microgrid system are enhanced to a certain extent,the impact of the microgrid system on the power system is reduced,and the security and stability of the power system are protected.(4)Comprehensive effect evaluation for capacity optimization and dispatching optimization of the regional interconnected microgrid system is studied.In order to test the effectiveness of implementation measures,the targeted index system is established from the four levels of economy,environment,society and technology.Combined with the interval two type fuzzy set theory,analytic hierarchy process and TOPSIS model,the comprehensive effect evaluation model of capacity optimization and dispatching optimization is established for the regional interconnected microgrid system.Firstly,the uncertainty of language expression information is processed by using the theory of interval two type fuzzy sets.Secondly,combining the above theory with AHP and TOPSIS model,the interval two type fuzzy AHP-TOPSIS model is established.Finally,taking five regional interconnected microgrid systems of the same scale as examples,apply the comprehensive effect evaluation model of interval two fuzzy AHP-TOPSIS to study and analyze the optimized and the unoptimized regional interconnected systems.The case results show that the evaluation results of optimized interconnected microgrid systems A1 and A2 are better than those of the unoptimized microgrid interconnected systems.At the same time,the important influence of environmental indicators on the comprehensive effect evaluation of the system is also clarified.The sensitivity analysis shows that the evaluation results are highly sensitive to the increase of employment opportunities in the indicators of social characterisics. |
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