Studies Of Grid-connected PV System's Impact On Grid's Operation And The Coping Strategy

Energy and environmental crisis has become one of the most important problem that obstructs the sustainable development of human being, while searching for the renewable clean energy sourses is the essential way out. Photovoltaic(PV) power generation is renewable, clean and getting more and more attention, which booms the PV power industry. But the output power of PV generation fluctuates randomly, which may interrupt the stably running of the grid when connected. In order to make the PV generation serve pople better, and to do good to the grid, we did some researches about the PV's influence on the grid's running in the article. And also gave out some advice to reduce it.First, the paper introducted the PV cell's generation principle, and the PV system's operation mode, and summarized the current improvement of the research about PV's influence on the grid. According the difference of the fluctuation speed of the PV's output power and the different influence on the grid's operation, the fluctuation was classified, as well as the PV system's access form. Then the study objects were established.Secondly, this paper established the model of PV system in which the PV cell's characteristics were simplified. That's suitable for the researching of PV's influence on the grid's steady-state operation. The paper chose the Benchmark's typical middle voltage distribution networks and micro-grid of low voltage as the study cases. Then simulated the influence on the grid brought by the PV system in different access form, under typical weather conditions. Advanced some suggestions combined conventional and new voltage regulating method, to reduce the influence.Again, according the actual fluctuations established PV system's output power model in different circumstances, which is suitable for grid's transient stability analysis. Simulated and analysed the grid's transient respones caused by the output power fluctuation of centralize-connected PV power generation station. Put forward the measures to improve system transient response.At last, established a common model which can reflect the charging and discharging rate and energy storage capacity limit of different kinds of energy storage systems. And demonstrated the effectiveness of the model by simulating experiment. The experiment also showed that the energy storage system improved the grid's transient response obviousely.