The Research Of Photovoltaic Grid-connected System Islanding

Now the serious energy crisis in the world is increasingly, the use of new energy is increasingly important, especially the use of solar energy. Photovoltaic grid-connected system is an important source of future grid power, the world photovoltaic grid-connected installed capacity increasing year by year, China’s photovoltaic grid also rapid development, but there are still many technical problems, such as Grid system control, islanding detection. Islanding detection related to the photovoltaic and reliable use of network energy, mainly on photovoltaic grid-island effect to make an in-depth analysis and research.Firstly, the photovoltaic grid-connected system overall analysis of introduction, and then harm derived by the analysis of the mechanism of islanding islanding islanding detection of domestic and international standards and islanding detection Research. And then mainly analyzes the anti-islanding detection methods, such as: some commonly used passive detection methods and active detection methods of their detection principle, and based on the theory of foreign mature to a more comprehensive comparison to currently used islanding detection method, and range of applications make a detailed description and analysis of their advantages and disadvantages. Make a detailed assessment of the islanding detection and comparative analysis of the advantages and disadvantages of the various coordinate assessment.Active islanding detection method described mechanism principle of the various initiatives detection method and validity analysis, analysis of some of the advantages and disadvantages of their existence in theory, proposed a new and improved detection methods, namely:based on the dq transform adaptive Active frequency shift islanding detection method of the detection principle, its feasibility is analyzed theoretically, and then create a simulation module and design parameters, simulation verify its effectiveness. Provide experimental basis for the research work of the PV grid islanding detection.