Transient stability analysis method of power system with vsg-iidg based on energy function

Abstract

The invention discloses a transient stability analysis method of a VSG-IIDG-containing power system based on an energy function. The virtual power angle characteristic curve of the inverter in different working states is fitted, and the virtual power angle characteristic is not changed under the premise of not changing. , so that the output electromagnetic power of the inverter and the virtual power angle have a unified model representation, so that the inverter can output power according to the fitted virtual power angle characteristic curve, and finally the system constructed according to the fitted and calculated electromagnetic power The energy function will strictly conform to the Lyapunov condition and can correctly judge whether the system is stable. The system energy function constructed by the invention has negative definiteness and can correctly judge the system stability, and the method is of great significance for analyzing the transient stability of the system including the VSG strategy inverter.

Description

technical field [0001] The invention relates to an inverter transient stability analysis technology, in particular to a transient stability analysis method of a VSG-IIDG power system with an energy function. Background technique [0002] Distributed power generation (DG) is mainly integrated into the large power grid through power electronic converters such as inverters, while traditional inverters cannot provide the necessary voltage support, frequency support and damping required by the current system for the power grid. The introduction of synchronous generator (VSG) technology has solved the above problems, but this type of inverter usually has a current limit control link. The inverter will fade into a current source, which will not only make the transient process of the inverter more complicated, but also change the virtual power angle characteristics of the inverter, which will affect the energy function of the system. [0003] Therefore, it is necessary to study the...

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Problems solved by technology

[0004] The purpose of the present invention is to provide an energy function-based transient stability analysis method for a VSG-IIDG power system to solve the sudden change of the magnetic potential energy of the system due to the change of the virtual power angle characteristics when the inverter current reaches saturation under the VSG strategy , which in turn leads to a sudden change in the total energy function of the system, which does not meet the Lyapunov condition

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