A decentralized stability analysis method for multi-fan grid-connected systems

Abstract

The invention relates to a decentralized stability analysis method for a multi-fan grid-connected system. The method first performs mathematical modeling on a permanent magnet synchronous fan, including a permanent magnet synchronous generator, a machine-side converter and its controller, and a grid. The mathematical model of the side converter and its controller and filter is linearized at the steady-state operating point through Park transformation to obtain the admittance model of a single permanent magnet synchronous fan in dq coordinate system. Multiply the admittance model with the network equivalent impedance model to construct the system return ratio matrix, and draw the characteristic curve of the system return ratio matrix. According to the requirements, draw the concentric circle curve of the number of parallel units, and analyze the stability of the multi-windows grid-connected system by comparing the relationship between the system characteristic curve and the concentric circle curve. The invention is based on the basic principle of the impedance analysis method and has better engineering practice value. Analyzing the stability of the overall system through the relationship between the impedance characteristics of a single wind turbine and the number of grid-connected units can better cope with the increase in the scale of wind farms, simplify the analysis process, and avoid repeated analysis.

Description

technical field [0001] The invention relates to a distributed stability analysis method for a multi-fan grid-connected system, which belongs to the field of stability analysis of power systems and new energy power generation systems. Background technique [0002] In recent years, with the rapid development of renewable energy, the installed capacity of wind power has continued to increase. As of September 2020, the cumulative installed capacity of wind power in the country has reached 223 million kilowatts. Centralized wind farms are the main form of collecting and sending out wind power. Each wind farm is usually equipped with dozens or even hundreds of wind turbines, which together form a multi-wind turbine grid-connected system. Permanent magnet synchronous wind turbine (PMSG) has the advantages of high energy conversion efficiency, good operation reliability and strong controllability, and the proportion of installed capacity continues to increase. However, PMSG uses th...

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Problems solved by technology

However, the traditional impedance analysis method is also unable to cope with the increase in the scale of wind farms. When the number of wind turbines increases, the impedance of the wind farm needs to be remodeled, resulting in repeated analysis.

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