Research On Optimal Sizing Of Distributed Generation And Energy Storage System In Microgrid

IThe stand-alone microgrid which is the integration of distributed generations,loads and energy storage devices is an effective measure that can solve the power supply problem of islands and remote areas.The sizing of the energy storage system and distributed generations should consider the condition of load,resources,properties of distributed generations as well as operating requirement of microgrid meanwhile find the equilibrium point of power supply reliability and economy.In this paper,the optimal sizing of distributed generations in traditional AC microgrid under improved charging strategy via artificial bee colony algorithm are studied.The conversion cost and loss is considered and environmental factors as well as power supply reliability are included in the economic model.Since the AC/DC hybrid microgrid can reduce the operation cost of conversion,the operation strategy is carried out aiming at the unique construction scheme and energy flow mode of AC/DC hybrid stand-alone microgrid considering the power transmission efficiency.On the premise of power supply reliability,active power distribution and charging and discharging control of energy storage are achieved by operation strategy.The optimal solution which meets the objective function and constraints is obtained using modified artificial bee colony.The Monte Carlo simulation is used to obtain the possible dispatch periods of electric vehicles,EV are divided into two types in each time step according to initial SOC: vehicles need to charge are regarded as loads;vehicles can either charge or discharge are regarded as energy storage devices to be dispatched.The microgrid operation strategy considering EV smart charge-discharge is proposed.Optimization program is compiled via Matlab,the annual meteorological data,annual load curve and related parameters of distributed energy are taken as the input data,the output of diesel generators,state of charge as well as charging and discharging power of storage battery,the power flows through converter and unmet load power all year per hour are determined by operation strategy.The minimum average annual cost is taken as the optimization target.By means of the modified artificial bee colony algorithm,the optimal sizing result of distributed generations are obtained.The results show that: 1)AC/DC hybrid micro-grid is proved to be more economical than AC microgrid and DC microgrid;2)The proposed operation strategy can lead to a more economical optimal sizing result with certain reliability of power supply;3)Comparing with uncoordinated charging mode and off-peak charging mode,the smart charge-discharge mode can obtain a more economical sizing result.