Research On Energy Optimization Method Of Regional Power Grid With Multi-microgrids In Market Environment

The development of smart grid technology has promoted the extensive access of largescale renewable energy and the vigorous development of demand-side response.Energysupplying members such as microgrid has the ability to make independent decisions,and they can effectively control distributed generators and flexible loads through energy management,which provides an effective way to make full use of demand-side distributed generators and load resources.With the reform of the electric power system of "opening up the selling side and cultivating the market main body through multiple ways",it can be predicted that,as a new market main body,in the future the microgrid will participate in the competition of the power market on the distribution side.For energy management of regional power grids with multiple microgrids,it is important to focus on how microgrids make competitive decisions to ensure their own profits in a multi-competitor market environment,and how microgrids cooperate with regional power grid to better integrate into market operation,and how regional power grid coordinates the interests of users in various markets,which can take into account the interests of all parties in regional power grid and microgrids,and can realize the balance of supply and demand.Therefore,research on energy management of regional power grid with multimicrogrids in the market environment is carried out as follows:1)This thesis analyzes the consumption characteristics of controllable micro source and the control characteristics of controllable load in microgrid,and then establish the basic mathematic models respectively.Subsequently,an energy optimization model of microgrid in market environment is constructed for the purpose of economy.Considering that the bidding strategy of microgrid in the market environment will directly affect the optimization results,the bidding model of microgrid based on comprehensive market power is further studied.A basic bidding model of controllable micro source based on marginal cost is established based,and a basic bidding model of controllable load based on energy constraints is also established.Finally,an overall basic bidding model of microgrid is synthesized.Considering that the basic bidding model only considers the user's own factors and is easily divorced from the actual market,this thesis analyses and quantifies the user's market power which directly affects the market clearing results,and improves the basic bidding model based on market power.What' more,this thesis uses analytic hierarchy process when determining the weight of market power index,so as to help users rationally adjust the quotation,which also lays a model foundation for later research.2)The needs of market users will be different in different market environments,their role in the market and the way of market development will also be different.In the regional power grid under unilateral open market and demand response environment,market users increase power or reduce load according to the dispatching instructions of regional power grid,and the power market is the main subordinate hierarchical structure.A double-layer energy optimization method for regional power grid with multi-microgrids is proposed according to the structural characteristics of electricity market.Market users formulate bidding strategies based on the improved bidding model proposed above.Regional power grid optimizes the clearing price and bidding power of each user with the goal of minimizing the purchase cost,and market users allocate the winning power according to the energy optimization model in the market environment.The simulation compares the market clearing results of the basic bidding model and the improved bidding model under different market power index weighting coefficients,and verifies that users can obtain more benefits when quote with improved bidding model,especially when the weight coefficient of market power index is consistent with the nature of self-regulation.At the same time,the regional power grid can collect network fees through organizing the market,and also can relieve the pressure of energy supply tension during peak load period,which has contributed to a win-win situation between regional power grid and market users.3)In the regional power grid under bilateral open market environment,buyers and sellers can directly carry out point-to-point electricity trading.The power market is a flat structure.A weakly centralized energy optimization method for regional power grid with multi-microgrids is proposed according to the structural characteristics of electricity market.In the market clearing stage,market users call the energy optimization model in the market environment and update the bidding strategy iteratively through the alternating direction multiplier algorithm,what's more,the regional power grid will verify the security and stability of the distributed iteration results,which restores the electricity market's characteristics of free competition and decentralized decision-making.The simulation example simulates the whole market development process,including task release,market clearing,transaction execution and settlement stages,and verifies the effectiveness of the proposed market mechanism.Compared with the non-open market,market transactions can realize the rational allocation of resources,cascade utilization of energy and peak-shaving and valley-filling of power grids,and can also improve the profits of market users and regional power grid.