Study On Siting And Sizing Of DG In Distributed Network Planning

To satisfy the demand of the rapid economic development in China, Vigorously developing Distributed generation(DG) technique based on existing central power stations and grids will become an inevitable trend for the power system development in the future. Distributed generation has many advantages, such as reducing the pollution to environment and lowing charge to users, improving quality of the electric energy and security of the power supply, easy tracking of power system to the load's change, be able to meet the requirements of sustainable energry development, so supplement and corresponding with the big electric network, distributed generation is the best way to supply the reliable and high-quality electric power to users by making good use of existed resource and equipment.As the extension of DG, it has a great impact on node voltage, power flow,short circuit and reliability of distribution network. The degree of impact is closely relative with the site and size of DG. It will be an essential challenge for network planning and grid must consider the influence of DG.This paper establishes economic model of DG based distribution network planning.The model takes the minimization of the investment and operation cost as objective function and builds normalized objective function by adding the node voltage constraints,wire current constraints, distributed power operation constraints that three inequality constraints through the punishment factor.In this paper, the whole capacity of candidate DG is determined by total load when considering the growth of system load. In the condition that DG's number,site and unit size are uncertain, the mufti-objective formulation with variable weights, which is convenient to apply for the grid planners, for the optimal sizing and siting of DG which is convenient to apply for the grid planners.Particle Swarm Optimization is used in network planning based on the capacity and the location of the individual DG, The economic indicators of the integrated planning results about distributed power and network are used to measure the merits of individual programs.Using the PSO algorithm to solve the mufti-objective optimization problem, and comparing of the analysis simulation results which not contain and contain distributed generators distribution network planning show that:distribution network planning with distributed generation have a reasonable optimization and superiority in some certain extent.From one side we can confirm that the distributed generation technology introducing into power system will bring more positive influences, but also confirm that the distributed generation technology has a broad application prospects.Through the second practical example, the analysis of PSO convergence performance than the genetic algorithm in a certain increase, optimization results as well as get a more reasonable position of distributed power supply and capacity of the program.