The Research Of The Black-start's Characteristic With Micro-grid

With the energy and environment crisis, many countries around the world are accelerated in the construction of intelligent power grid to ensure the safety and stability of power system. Micro-grid technology is the key point of the construction of intelligent power grid. When power system needs to undertake black-start after collapse, micro-grid can shorten the time of black time and make black-start process more stable because the existence of micro-grid has changed the characteristic of original power system. Therefore, the research of properties of micro-grid is very necessary and important. Based on the research of key technology of intelligent power system, the paper, first, analyzes the problems of self-excitation of modern power system routine black start, over-voltage of rack convalescence and frequency fluctuation of load convalescence. These problems existing in regular black start may lead to instability of power system and further lead to failure of the black start, power equipment damage and so on. And after modeling and simulation, the severity of these problems and the necessity of solution are concerned.Secondly, according to the power system containing micro-grid, the paper analyzes the operation characteristics of micro-grid interface (PCC) and the control strategy during the period of preparation, rack recovery and load recovery. Based on real-time detection of voltage and frequency, this strategy adjusts the operation mode to control the micro nets outlet power. The paper puts forward the black start project of power system containing micro-grid, and verifies its rationality through the simulation of MATLAB.Finally, the paper analyzes the real network of A through simulation. Because the type of A power grid is hydropower primarily, the No.9 power plant of A serves as a black start power plant of power grid in conventional black-start project. The paper compares the system black-start characteristics of conventional power system and the power system containing micro-grid during the load recovery period, and proves the important role micro-grid construction take in the safe, stable and quick process of black-start.The characteristics of micro-grid are considered in the black-start of power system, and many problems appeared in the regular black-start are avoided. So the technology of micro-grid plays an important role in the power system for safety, stability and economic benefit.