Optimal Allocation Of Distribution Network Considering Stochastic Characteristics Of Distributed Generation

In recent years,under the situation of electric power reform and the development of new energy,distributed generation has attracted more and more attention because of its clean,environmental,efficient and friendly feature,and wind power,solar photovoltaic power generation as the representative,has got rapid development in many regions and many fields.The combination of power grid and distributed generation to provide high quality power to users is a major development direction of the power system.When distribution generation has accessed to the power grid,it's able to improve the reliability of power supply and reduce the network loss.However,the unreasonable location and capacity of distribution generation will also affect the relay protection devices of power system and bring a series of destabilization to system.The location and output power of these distributed generators will be affected by natural conditions and could be uncertain.When distributed generation is connected to the grid,there will be some impact and challenge to the planning of the power grid.Therefore,it is necessary to optimize the distribution of distributed generation when it is connected to the distribution network.Optimal allocation of this paper of distributed generation access to distribution network is in the context of the existing distribution power system wiring and operation mode has been determined,to study optimal access location and network capacity of distributed generation and enable it to maximize the performance indicators of distributed system.This paper analyzes the influence the five aspects of the distribution network planning,network loss,reliability,power quality and relay protection when the distributed generation access to distribution network.A random flow calculation method based on the semi invariant and Gram-Charlier series is proposed to calculate the distribution network with distributed generation.The paper verifies the validity of the method by simulation and analysis the influence of distributed generation on distribution network through the simulation.Based on the reliability and economical efficiency of distribution network working,this paper establishes the distributed generation multi-objective model for active network loss,voltage stability index and distributed generation investment cost as the objective function,and considers the needs of power balance,voltage and capacity to meet the following equality and inequality constraints.An improved particle swarm genetic algorithm(PSGA)is proposed to optimize the multi-objective model,combining the advantages of particle swarm optimization(PSO)and genetic algorithm(GA).This paper uses the IEEE33 node distribution system to carry out the simulation,and obtains the reasonable location and capacity for distributed generation to access the distribution network.By comparing the changes of the three objective function,paper has proved the feasibility of this model and multiobjective optimization algorithm.The other part of simulation is the comparison between the improved Particle swarm genetic algorithm and traditional particle swarm optimization,genetic algorithm which shows the proposed algorithm has certain advantages in the calculation speed,convergence precision etc.