Optimal Allocation Of Distributed Generation Considering Environmental Benefits

The mutual combination and complement of distributed generation and large power grid is recognized as the main approach to save investment, reduce energy consumption and improve the safety and flexibility of the system, which is main development trend of the electric power industry in 21st Century. Network-connected distributed generation brings great impacts on voltage distribution, network losses, system protection and reliability of distribution network. Reasonable site and size of distributed generation is important to ensure the environmental protection, safety, reliability, economy of the system. Many countries and regions put forward the development strategy of smart grid. An important feature of smart grid is that it has good compatibility for distributed generation. So, the research on the optimal allocation of distributed generation must be paid great attention in developing smart grid.The definition, classification of distributed generation and its network-connected technology is instructed. The general operation guidelines are revealed primarily after several simulations in open loop feeders where the distributed generations'outputs change, locations change and operation modes change. The results show that distributed generation can provide voltage support, reduce or increase network loss. So, reasonable planning for distributed generation in the distribution network must be adopted to give full play to the benefits and restrain the negative effects.Aiming at the current situation that the environmental benefits of distributed generation can't be quantified, some indices are introduced to quantitatively analyze the value of environmental benefits. Meanwhile, a new mathematical model for calculating the generation cost of distributed generation is established. The model considers the environmental cost of pollutant emissions of power generation, which contains the environmental of pollutant emissions value and pollution charge.A mathematical model for optimal allocation of distributed deneration is established based on considering the safety of power system. The model takes the sites and sizes of distributed generation as variables and minimum operation cost as objective function, considering the environmental cost of different power generation. The particle swarm optimization algorithm is proposed to solve the optimization model. Some corresponding techniques, such as particle representation of candidate solutions, handling of constraints, construction of fitness function, the selection methods of algorithm parameters, are studied deeply and comprehensively. The results of a practical distribution system show that the method proposed can get reasonable site and size of distributed generation, greatly improving the economics and environmental protection of the power system.