Research On Control Strategy And Spare Capacity Optimization For Primary Frequency Modulation Of Microgrid

With the development of economic technology,the traditional fossil fuel has been drastically reduced.The new energy generation represented by the microgrid has developed rapidly.The microgrid can supply power to the nearest load,which can reduce the loss of electric energy in transmission and can be greatly reduced pollution caused by traditional thermal power generation.For microgrids operating in remote areas using islands to solve the problem of electricity consumption,the current situation of traditional energy shortage has been greatly alleviated,but the frequency stability also has been challenged after the increase of distributed power penetration in the microgrid.Therefore,it is important to make the microgrid have the ability to regulate frequency.In this paper,the characteristics of primary frequency regulation response of power system under different wind power penetration rates are studied.It is indicated that with the increase of permeability,the system needs to reserve a certain spare capacity.The characteristics and output model of distributed power supply in microgrid are studied.The technical and economic characteristics of the energy storage battery are analyzed in detail.The TFN-AHP method is used to authorize the technical economy and environmental protection factors of the energy storage battery,and select the optimal energy storage type for the micro frequency network.The control strategy of the wind-fire-storage primary frequency regulation of the microgrid is studied.In order to prevent the overcharge and overcharge of the energy storage in the frequency regulation,the control strategy of the energy storage variable droop coefficient based on the state feedback is considered,and the simulation is carried out in DIgSILENT.The validity of the proposed strategy is verified by an example.In order to solve the problem of primary frequency reserve capacity of the island running microgrid,a method of optimal configuration of the system’s primary frequency spare capacity is proposed by using chance constrained programming.With opportunity-constrained planning,it is possible to obtain the energy storage power value that needs to be configured for a good primary frequency regulation capability under different confidence levels,and meet the certain confidence level to make the cost of system comprehensive frequency regulation lowest.The correctness of the proposed method is verified by an example.