| With the rapid development of wind power generation, the problem brought by its large scale grid-connected is becoming increasingly prominent. With the gradual perfection of energy storage technology, its rationally control can smooth wind power fluctuations, improve grid wind power quality, is an effective approach for the above problem. All vanadium redox flow battery as a large-capacity storage device has many advantages such as high efficiency, can be deeply charged and discharged, the power and capacity can be designed independently, so it has great development potential in the field of large-scale energy storage. Power system simulation and calculation is important for the power system operational controlling and planning, what’s more, accurate simulation models is the foundation of power system simulation and calculation. Therefore, building suitable model of all vanadium redox flow battery energy storage system for grid simulation, and study its application in wind power system have important theoretical and practical significance.Firstly, this paper has a detail description on the working principle, energy storage mechanism and ion diffusion theory of vanadium redox flow battery. After summarizing the modeling status quo at home and abroad, this paper presented a new type equivalent circuit model, which considering the effect of ion diffusion. A mass of simulations were conducted in different states to study the effect of ion diffusion imposed on outer characteristics and capacity of the battery, as well as cycle period.Secondly, this paper used grid-connection control strategy, that the DC/DC converter using voltage outer loop and current inner loop control strategy, and the DC/AC converter using PQ (active power and reactive power) control strategy for its application in wind power generation system. Based on the Matlab/Simulink simulation platform, this paper built a detail digital simulation model of integrated vanadium flow battery energy storage system, the effectiveness and correctness of the energy storage system and its grid-connection control strategy were proved by simulations. The vanadium flow battery energy storage system is used to smooth wind power fluctuations, using the smooth control strategy based on high-pass filtering principle, using wind power run data of Zhang Bei national wind/photovoltatic/energy storage and transmission demonstration project to simulation test, simulation results show that the model has good smooth effect. Based on steady state and transient characteristics of the all vanadium flow battery energy storage system, this paper proposed a electromechanical transient model, a U-R-L equivalent circuit, second-order dynamic differential equation dynamic model which can accurately simulate the system’s equivalent characteristic, but also can meet the demand of power grid simulation. The validity, generalization ability, parameter stability and its adaptability for the typical control strategies are testified by comparison simulation modeling with different disturbance levels. Finally, the model application and description ability for similar battery energy storage systems are studied by modeling practice... |
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