I. Introduction
Along with the development of intelligent distribution network, energy storage technology as one of the key technical of future distribution network plays the role of peak cut and valley fill restraint of the volatility of distributed power generation, increasing the quality of power supply and so on in the power system. obtain more and more attention are obtained by the power industry [1]. The relevant research on its connection to the distribution network is also going on. The rapid development of energy storage materials and electric power technology facilitates the gradual development of more and more new energy storage technologies, such as superconductivity battery, lithium-ion battery, compressed air energy storage, etc. There is also breakthrough in the research on the lithium-ion battery, flow cell, compressed air energy storage and so on which are suitable for large-scale energy storage [2]. The development and breakthrough set the foundation for the application of ESS into the power supply system. The energy storage technology has already become the sixth element apart from the other five elements of power generation, electricity transformation, electricity transmission, power distribution and power consumption in the operation of power grid.