Abstract: The practical demand of plug and play（PNP） function for battery energy storage power station（BESPS） based on the emergency support and scale application background of battery energy storage is presented in this paper.By analyzing the typical structure of MW BESPS in Zhenjiang,Jiangsu Province,which was put into operation in July 2018,it is proposed for the first time that the key technologies for that PNP operation of BESPS should be considered from two dimensions of energy flow and information flow.According to the requirement of hierarchical communication at information flow level,a self-describing model establishment method and information interaction mechanism of grid-connected BESPS are proposed,and the concrete realization method of hierarchical communication is expounded.Considering that the technical requirements of the physical interface integration drive at the energy flow level,the control strategy of multi-state smooth switching,active voltage ＆ frequency support,peak-load shaving,black start and other advanced applications for BESPS is studied and summarized.Finally,the multi-state smooth switching control algorithm at flexible access and exit response process of BESPS energy flow level is validated by simulation.The research work in this paper has a very positive guiding significance and reference value for the development of enhanced BESPS and solving the problems of large-scale and flexible grid connection of BESPS.