Research On The Optimal Operation Strategy Of Micro-grid Based On Improved PSO

With the increasingly outstanding contradiction between energy demand and environmental protection, the development and utilization solar energy, wind energy and other clean new energy has become an important component of energy supply, which are also the national strategy of key support areas. To improve the utilization efficiency of new energy, distributed power generation technology has been proposed, which is also a hot topic in this field, but the cost of single access is high and the control is difficult. Aiming at the solving the problems, the concept of the micro grid is put forward. Micro-grid, a single independently controllable power system, consists of micro power supply, load, energy storage device and control system, which can increases the reliability and flexibility of the grid, make full use of new energy sources such as solar energy, wind energy, optimize the structure of electric energy and reduce pollution emissions. Due to the diversity of micro power and its flexible combination in the Micro-grid, the research of Micro-grid optimal operation is necessary.Firstly, this paper introduces the background and significance of Micro-grid, analyze the research status at home and abroad and research results of its operation optimization. Then, this paper expounds the working principle of typical micro power and its structure characteristics. According to the operation characteristics of the photovoltaic cells, wind turbines, fuel cells, miniature gas turbine and energy storing device, the mathematical model of micro power supply is made. Meanwhile, considering the power flow constraints, power balance constraints, micro power output power constraints, node voltage constraints and so on, the objective function of Micro-grid optimal operation is built, which includes fuel costs, operation and maintenance costs, environmental penalty cost. Because the ergodicity of traditional particle swarm optimization is not good,easy to fall into premature, this paper proposes an improved particle swarm optimization algorithm. There are two aspects of the improvement. On the one hand, linear differential decreasing inertia weight and learning factor linear adjustment are introduced on the basis of traditional particle swarm optimization algorithm. On the other hand, the combination of particle swarm algorithm and chaotic thoughts makes particle swarm algorithm based on chaotic thoughts, which increases particle of ergodicity, randomness and enhances the diversity of population. A variance value is set to determine the existence of early maturing process of particle search, which makes particle swarm optimization result not easily trap into local optimal solution.Lastly, this paper adopts the Micro-grid system with the IEEE-14 node as the research object of operation optimization. Accroding to the different load demand and different environmental factors of the spring and summer, the minimum objective function is adopted as the optimal operation strategy, which analyses grid state and isolated network in the way of simulation, optimizes the output power of Micro-grid at different time, makes operation cost minimum, and gets the best operation status. The simulation results demonstrate the superiority and effectiveness of improved particle swarm algorithm and Micro-grid operation mathematical model.