Energy Storage Capacity Configuration In Microgrid

With the history developing and the innovative technology, the whole world is in the rapid construction, while the energy is facing depletion. Therefore, the efficient use of renewable energy has become one of the themes of the world nowadays. As an industry which has great demand of energy, power systems need more new technologies to cater to the pace of the development of smart grid. Electric power network in China set power generation and long distance transmission as a whole, as the requirements of users about the higher power quality and the more electricity load, the delivery capacity for long transmission line is increasing, which greatly affected the stability and security of power grid operation. So the traditional mode of operation of large power grid has been unable to meet the social requirements. With the continuous exploration of the power grid operation mode, new energy micro grid technologies like wind power turbine and photovoltaic power generation and other generators have begun to enter the people’s vision. However, because of the intermittence and randomicity of such technologies, the effect is not well reflected now.Adding the energy storage device to micro grid can not only improve the characteristics of the output power of generators, it can also improve the stability of wind turbine and photovoltaic while connecting to the big power grid. What’s more, the energy storage can provide short-term electricity to the load and is good for peak shaving. The development of energy storage system lags behind relatively because of its high cost. The rational allocation and costs decline are crucial to the development of energy storage technology. Based on the above background, this paper carry out the following research work:Firstly, discuss the basic model of each part in this project, including energy storage device, photovoltaic device, wind turbine device and diesel engine unit. Also study on the load characteristics of every situation. The basic output power calculation model and the corresponding cost analysis are established in view of each part.Secondly, improve the algorithm by combining the merits of biogeography based optimization algorithm and particle swarm algorithm. This part describes the combination of principle and process steps of the new algorithm.Then, using the improved biogeography based optimization to discuss the following three issues. The first is to discuss the configuration scheme of peak shifting. The paper describes the effect and the basic requirements to realize the peak shifting with energy storage device, then gradually establish an income analysis mathematical model corresponding basic requirements and set the objective functions and constraint conditions. At last, verifies the applicability of the algorithm on such issues through a specific example of data analysis and discussion. Second is the independent system with wind turbine, photovoltaic device, diesel engine and energy storage device as backup power. Set up the corresponding cost mathematical model, objective functions and constraint conditions. Calculate the best proportion of various components of the system with specific examples, and compare the improved algorithm with the general algorithms, which embodies the superiority of the new algorithm. The third is about stabilizing the power fluctuation of generator. This part expounds the function, effect and basic requirements of stabilizing the output power fluctuation. It also establishes the mathematical model of costs, the objective function and the constraint condition. At last, verify the feasibility of this kind of improved algorithm by example simulation with half-true, half-simulation data.Aiming at the problem of the cost of energy storage device, this paper shows the study about the best energy storage capacity configuration combined with the optimization algorithm, reliability theory, mathematical modeling, cost analysis and nonlinear problems and other theories, which is adapted to the development under the new situation. This thesis is exploring, and has a good theoretical reference value and application prospect.