Research On The Integrated Relay Protection Strategy Of Micro-grid

Energy exhausting and environmental pollution problems make the distributed power generation technology get a fast development. Micro power grid, as the effective way of using distributed generation, solve the problem of the distributed generation large-scale application. However, distributed generation is lack of inertia and has a poor stability.The system of short-term fluctuations could lead to a distributed generation running out of supply. In addition, the number of distributed power supply in the micro-grid is small, but the percentage of the single power supply in the whole system is huge. When a single power supply exits, it could make a huge impact on the system. This makes protection problems become one of the biggest technical barriers, which restrict the development of the micro grid.The paper conducts a thorough research to the micro grid relay protection strategy in order to improve the protection reliability, and set a micro photovoltaic (pv) grid simulation model. The existing protection method for micro grid is studied and analyzed, and the principle and advantages and disadvantages of the existing methods are summarized in the paper. The paper analyses the effect of micro-grid access to distribution network, aiming at the complexity of the micro-grid relay protection, designing a comprehensive protection strategy based on a combination of negative sequence voltage and negative sequence power direction element. The simulation on the function of comprehensive protection strategy done, the results show that the integrated relay protection strategy can accurately locate fault source and remove it in the smallest range.