The energy storage

due to such advantages as large peak adjustment amplitude and fast response speed

can supply multiple such services for the grid operation as peak and frequency regulation

backup

black start and demand response

and is important technical means in improving operation flexibility and safety of grid.In recent years

the energy storage technology

under the stimulation of favorable national and local policies

develops very fast from gradually distribution energy storage with small capacity and scale to the concentrated energy storage development with large capacity and scale.The electrochemical energy storage

due to such technical advantage as fast response speed

high energy density and high cycle efficiency

has become the key area and major growth point in the innovation of energy storage industries in various countries.The current research is mainly focused on the small-capacity electrochemical energy storage proper and its influence on small-scale distribution/micro network.In this paper

equivalent simulation models for the large-capacity energy storage station are conducted respectivelyin accordance with such two methods as Thevenin theory and simulation controlled-current source.The correctness of equivalent simulation model is verified by the comparison with the complete simulation model.From simulations of system-connected operation characteristics for the large-capacity energy storage station

its transient characteristics during three-phase and single-phase short-circuit faults are different from those of the traditional AC（Alternating Current） system is found.Therefore special studies for transient characteristics needs to be performed with integrations of the large-capacity energy storage stations.