Applied Technology Research Of Distributed Energy Access To The Grid

As the energy crisis caused wide public concern all over the world, the developing and using of clean energy has become an important way to solve this problem. Due to the element of clean, small unit capacity, flexibility, installed in the load point for the user to NDF, the reliability of power supply has been improved by the distributed energy. With kinds, distributed generator has been installed near the loads, especially the photovoltaic and wind power. In order to research the related technologies of distributed energy system access to the grid and using the energy in maximum, the influence of the distributed energy of harmonic, relay protection of distribution network as well as the island effect have been researched. And then analyzing the superiority of distributed energy from the aspect of energy-saving emission reduction. Finally, the technical requirements for grid connected of distributed energy and measurement methods have been proposed.Distributed energy access the grid affects the quality of electric. The voltage and frequency would be influenced because of the intermittent of distributed energy and leading to the harmonic pollution directly. As an example, the data of two photovoltaic power stations and two wind farms in Shanghai, Chongming Island has been collected. By analyzing the harmonic ratio of voltage and current. The result shows that photovoltaic power, voltage harmonic ratio with 95% probability reached 1.36%, not exceeding the national standard of 4%. The harmonic influence of phase A might be occurred but controlled in the range of station standard. The measures to restrain harmonic has been proposed in the paper in order to control the harmonic pollution within the standard in the condition of distributed energy proportion increasing rapidly.The structure of distribution network would be changed when the distributed energy access to the grid and the relay protection may also be affected accordingly. To a distribution network, the simulation of system with PV has been progressed in the environment of PSASP7.1. The result shows that influence of protection would be taken with different capacity and the position of distributed energy, also to automatic reclosing. When the fault occurs, the method of islanding detection has been proposed in the paper.The popularization and application of distributed energy partly replaces the traditional energy sources, and has brought considerable economic benefits due to its clean for energy saving and emission reduction. The evaluation model of reduction and the environmental benefits has been put forward. Taking 10 MW as an example, the effect of energy saving and emission reduction has been calculated.Distributed energy has an impact on the power system. In order to ensure the system to work in the safe, stable and reliable operation, the related standards must be satisfied to the grid with distributed energy. The standards of State grid and Shanghai grid have been proposed in the paper. And listing the interconnection standards in different regions for photovoltaic generation. In addition, the metering modes with distributed energy has also been presented in the paper.Researching on issues related to the residents of distributed energy system, not only provides a theoretical support for effective to alleviate the energy crisis, provides protection for the use of clean energy maximum, but also supplies an important way to achieve energy-saving emission reduction and an important way to achieve sustainable energy development path.