Research On Planning Methods Of Energy Storage System For Distribution Network

As large-scale distributed generators access to the power grid, the randomness and volatility of its output will have a great impact on the safe and stable operation of the grid. Energy storage has a bidirectional energy flow capacity, through charging and discharging rapidly, it can alleviate the adverse effects of distributed generation. At present, the energy storage device has a high costs, while the location has a large influence on its smoothing effect, it is necessary to study the location and capacity configuration of energy storage. In this paper, planning methods of energy storage system for distribution network are studied.Firstly, the applications of energy storage system in distribution network are analyzed. It can be used in key points of distribution network and micro-grid system, and the roles of the energy storage system have been respectively analyzed.Secondly, as for energy storage system applies to the key points of distribution network, a method for energy storage locating and sizing based on improved multi-objective particle swarm optimizer is established. On the basis of the benefits and costs of the energy storage devices, the voltage fluctuation of system nodes, load fluctuation, and the total capacity of energy storage system are taken as the optimization objective. And an improved multi-objective particle swarm optimizer is proposed. To avoid the influence on the final result from decision makers, the technique for order performance by similarity to ideal solution based on the entropy is adopted to choose the optimal solution from Pareto solution set. Simulation results show that the method and the improved algorithm are effective.Then, the optimized capacity configuration of energy storage device for stand-alone photovoltaic generation system is studied. Considering the reliability and economic of power supply, an optimization model of energy storage capacity, in which the loss of power supply probability and energy excess percentage are taken as assessment indices, is proposed. The paper also considers the dynamic variation of stored energy and takes technical characteristics of energy storage unit as the constraint. According to different known conditions, two modes are considered, configuration of energy storage capacity and joint configuration of PV capacity and energy storage capacity. Taking valve regulated lead acid battery, lithium-ion battery and all-vanadium redox flow battery into account, the capacity of the three kinds of batteries are configured and the simulation results verify the effectiveness of the proposed method.Finally, according to the research contents, an energy storage planning analysis software is developed by using MATLAB GUI, making the research findings have better versatility and maneuverability.