Studies Of Effects Of Distributed Energy Storage On Operational Characteristics Of Micro-grid

Micro-grid can ensure the reliability of power supply, improve power quality, intensive the application of new energy and has unique advantages in the cascade utilization of energy, also helps the grid strengthen the capacity of disaster response. Micro-grid is also in the form of the active controlled load into the smart grid. However, there are also problems such as power quality and the impact on the main network. The development and application of the energy storage technology have provided one kind of new way for the problem solving. In order to achieve the technical characteristics of micro-grid better, electric energy storage technology is regarded as one of the core technologies in micro-grid, which plays an important role for utilizing renewable energy with high efficiency and on the stable operation of micro-grid.First, this paper analyzes the characteristics of several important DG in micro-grid. We establish the prime mover mathematical model of micro-turbine of AC microsource and the mathematical model of photovoltaic array of DC micro-source and the corresponding control strategy of grid-connected operation and isolated operation. Then we focus on distributed energy storage systems, including super-capacitor and battery. Battery has the characteristic of large capacity and super-capacitor has the characteristic of fast response. Battery and super-capacitor are used to achieve the energy management.In the depth analysis of the structure of micro-grid and the properties of distributed generation and the control strategy of the system, based on the laboratory construction report of micro-grid in North China Electric Power University and the classic reference of CERTS micro-grid model, the overall integrated simulation system of micro-grid contains variety of DG is built in the PSCAD platform. Through the simulation of micro-grid in the grid-connected mode, the isolated operation mode, from the grid-connected to the isolated operation mode, we research on the mechanism of the interaction of distributed energy storage system and micro-grid. Simulation results show that the distributed energy storage system can regulate the micro-grid voltage and frequency and stabilize the system disturbance and ensure the stable operation of micro-grid.