Wind power plant grid-connection stability analysis method considering dynamic characteristics of permanent magnet directly-driven wind turbine generator

Abstract

The invention discloses a wind power plant grid-connection stability analysis method considering dynamic characteristics of a permanent magnet directly-driven wind turbine generator. The wind power plant grid-connection stability analysis method comprises the steps of S1, building a simplified dynamic model of a PMSG (Permanent Magnet Synchronous Generator) type wind power plant grid-connection system, and acquiring equivalent output impedance of the PMSG type wind power plant grid-connection system; S2, acquiring equivalent input impedance at a grid side of the PMSG type wind power plant grid-connection system by using a Thevenin equivalent method; S3, calculating an output and input impedance ratio Tm of the PMSG type wind power plant grid-connection system; and S4, judging the stability of the PMSG grid-connection system by using an output and input impedance ratio stability analysis principle. From the aspect of frequency domain stability, the wind power plant grid-connection stability analysis method considers main relevant factors of dynamic characteristics of a PMSG, puts forwards a concept of the output and input impedance ratio Tm of the wind power grid-connection system, constructs a specific expression formula of the indicator, and ingeniously uses an Nyquist curve of the output and input impedance ratio Tm to judge the grid-connection stability of the system.

Description

technical field [0001] The invention relates to a method for analyzing the grid-connected stability of wind farms, in particular to a method for analyzing the grid-connected stability of wind farms considering the dynamic characteristics of permanent magnet direct drive wind turbines Background technique [0002] New energy represented by wind energy and photovoltaics has been widely valued and developed rapidly around the world. Among them, wind energy utilization and wind power generation technologies are the most mature. The permanent magnet direct drive wind turbine (Permanent Magnet Synchronous Generator, PMSG) has the advantages of high efficiency, reliability, small mechanical stress, and no speed change link, and has become the development trend of wind power generation. Compared with the traditional power supply, PMSG is a non-ideal power supply. After cascaded with the converter and connected to the grid, it will cause fluctuations in the voltage and power of the ...

AI Technical Summary

Problems solved by technology

Compared with the traditional power supply, PMSG is a non-ideal power supply. After cascaded with the converter and connected to the grid, it will cause fluctuations in the voltage and power of the power system, large impact caused by excessive transient overshoot, and system stability degradation.

[0003] At home and abroad, the analysis of PMSG grid-connected stability is mostly limited to the external characteristics of the unit after grid-connected, ignoring the dynamic characteristics of its converter and generator set, and cannot accurately judge the stability of the system

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