| Microgrid is an effective way to protect the environment and absorb renewable energy.The DC microgrid has the advantages of good power supply quality,low line loss,and easy control.It does not have the problems of frequency and phase that exist in the AC microgrid.However,a single microgrid cannot guarantee a good power supply quality due to its limited capacity and other reasons.In order to improve the reliability of power supply,multiple microgrids can be connected to form a microgrid cluster system.The power exchange between the microgrid and the microgrid can improve the stability and reliability of the power supply,and can also consume more renewable energy.For the microgrid system operating in an island,in order to meet the demand of the load and consume renewable energy,the energy storage battery system often has the phenomenon that the charging and discharging power is too fast or the discharge depth is too large.After the microgrid group system is formed,the energy storage battery can be protected to a certain extent through the power dispatching between the microgrids.The traditional centralized optimization has problems such as difficult large-scale solution,extremely high communication requirements,and difficulty in ensuring the privacy of each microgrid.In view of the problem that the microgrid operating in an island cannot protect the energy storage battery,multiple microgrids can be organically connected to form a microgrid cluster system.An optimal scheduling strategy for microgrid clusters considering energy storage batteries is proposed.The influence of chargedischarge depth and charge-discharge rate on the life of energy storage batteries is studied,and the optimal scheduling model of micro-grid group is established with the goal of minimizing the cost of micro-grid group.The effectiveness of the strategy is verified by a general microgrid cluster example.Compared with the case where the energy storage battery is not considered,the strategy greatly reduces the life loss of the energy storage battery,and at the same time reduces the power dispatching between microgrids,saving energy cost.Aiming at the problems of centralized optimization,on the basis of considering the life of energy storage batteries,a two-layer optimization scheduling strategy for microgrid clusters considering energy storage batteries is proposed.This strategy divides the optimal scheduling of microgrid groups into two types: optimal scheduling among microgrids and optimal scheduling within microgrids.The upper layer adopts the synchronous alternating direction multiplier method to transform the asynchronous iterative process into a synchronous iterative process.The solution process can be completed only by transmitting the desired scheduling power.The lower layer adopts the idea of model predictive control,which reduces the influence of wind power generation,photovoltaic power generation and load fluctuation.The effectiveness of the strategy is verified by an example of a general-purpose microgrid group.The layered strategy provides the possibility to simplify the upper-layer optimization model.The simplified model makes the algorithm converge significantly faster.Compared with the centralized strategy,this strategy The optimization results are smoother,the loss of energy storage batteries is slightly reduced,the power scheduling between microgrids is reduced,the pressure of information transmission is reduced,and the privacy of each microgrid is protected. |
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