Research On A Utility-driven Energy Sharing System In A Community Microgrid

In order to save energy and protect the environment,many countries are actively promoting renewable energy generation,especially solar power.As more and more houses are equipped with photovoltaic power generation systems,the traditional mode of “self-generation self-use,surplus power feed into main grid” not only has a certain impact on the stability of the main grid,but also the low price of surplus power can’t meet the user’s interest.In addition,because the photovoltaic power generation characteristic curve and the load characteristic curve are inconsistent,the problem of imbalance between power supply and demand of a single user is caused.In order to solve the above problems at the same time,this paper proposes a method of sharing energy between users in a community microgrid,that is,users with surplus energy can sell energy to users with insufficient energy.Therefore,the research content of this paper is to establish an energy sharing system in a community microgrid,and explore a utility-driven sharing mechanism to maintain the stable operation of the system.The main contributions of this paper are as follows:1.An innovative dynamic adaptive system for energy sharing in a community microgrid based on cloud energy storage architecture and time window prediction transaction is proposed.Cloud energy storage architecture overcomes the difficulty of installing energy storage devices on the user side.Time window forecasting transaction is a suitable method for energy trading in a microgrid.At the same time,the system has dynamic adaptive characteristics and can automatically adjust to the optimal time window.2.A centralized energy sharing mechanism based on dual incentives of price and priority index is proposed,which solves the problem of energy pricing and distributing in a community microgrid.Energy sharing is centrally controlled by a Distribution System Operator(DSO),which is divided into two stages: DSO collecting energy and DSO distributing energy.In the stage of collecting energy,an optimal pricing algorithm is proposed to maximize the seller’s utility and minimize the DSO purchase cost.In the stage of distributing energy,an energy distribution algorithm based on priority index is proposed to maximize the buyer’s utility.3.A compensation and clearing model for energy prediction errors is proposed,which solves the problem of economic loss caused by forecasting errors.The time window is divided into three stages.In the first stage,transaction entities sign the contract after the system runs the sharing mechanism.In the second stage,the transaction entities execute the contract based on the actual state of energy.In the third stage,they judge whether the contract signed in the first stage is fulfilled in the second stage.If there is economic loss caused by default due to prediction error,it will be borne by the transaction entity.The experimental results show that all buyers and sellers in the community microgrid actively participate in energy sharing in order to maximize utility.First of all,the energy pricing algorithm and the allocation algorithm proposed in this paper can converge quickly within 1 second,which ensures that the energy sharing can be completed in a short time even if the grid communication has a high delay.Secondly,compared with ‘surplus power feed into main grid’,the energy exchange between the microgrid and the main grid in the energy sharing mode is reduced by an average of 72.6%,the buyer’s electricity purchase cost is decreased by an average of 46.2%,and the seller’s electricity sales profit is increased by an average of 62.5%.