Sitting And Sizing Operation And Island Partition For Distributed Generation Based On Improving Energy Efficiency

Proposing and constructing the smart grid can solve the problems of energy shortage and environmental pollution. It can also provide opportunities for the development of renewable energy. Distributed generation as one of the major feature of the smart grid has the characteristics of short construction period, installation location flexibility, high reliability, high heat efficiency, clean environmental protection and so on. Micro grid as an effective carrier of distributed power can give full play to the advantages of distributed generation, can further improve the economical benefit, flexibility and clean of the power system, also can better meet the requirements of the user side of the power quality and power supply reliability. The position and capacity of different types of distributed generation will influence the distribution of micro grid power flow directly. It is mainly reflected in the cascade utilization of energy, power grid planning cost, power supply reliability, power quality, network loss and relay protection, etc. The controlled island is a new operation mode of distribution network after introducing the distributed generation technology. Distribution network is a kind of typical and complex network. When fault occurs in the distribution network, only a smooth transition to the planned island state can truly make full use of structure optimization of the distribution network. The paper discussed two aspects. The main research work is as follows:(1) The paper study multiple distributed generations, including micro-turbine generator, wind-turbine generator, photovoltaic and storage battery.(2) By considering the case of a certain DG capacity and uncertain number and location, the minimum of the user side investment and transmission loss cost is taken as the target function. Weight coefficients are set combining with the importance of cost. A multi-objective optimization model is built. Ant colony algorithm is used to get the optimal location and capacity of DG. Applied the method to the30nodes distribution system and finally get the optimal scheme. Example analysis shows that the method is reasonable. It can effectively reduce the network loss and node voltage deviation. And it can improve the economic benefits of demand side and power quality.(3) The paper proposed islanding scheme according to the user side demand and the optimization position and capacity results. The scheme add the importance of demand side load, give distributed generation power priority to the important load to ensure uninterrupted power supply, and give the rest of the electrical energy to the secondary load. There exists a variety of ways to fuse nodes, so it needs combine objective function and constraint condition with all these ways to choose the most suitable and optimization islanding scheme. The paper take the optimized grid connected distributed generation of the IEEE30nodes distribution network as the example to validate. Example analysis shows that, the islanding scheme based on the fault of the optimized grid connected distributed generation is reasonable and can fit the demand side well. The load and the capacity in the fusion elements can reach a high degree of adaptation. The results improve the reliability and self-healing ability of the distribution network.