Transient state power angle stability analysis method for wind power plant-containing multi-machine system

Abstract

The invention discloses a transient state power angle stability analysis method for a wind power plant-containing multi-machine system. The transient state power angle stability analysis method comprises the steps of disclosing a mutual synchronicity principle for influencing the power angle of a synchronous machine by a double-fed wind power plant by means of transferring active and reactive power to a power grid for realizing electrical interaction with the synchronous machine, and reflecting the externally output power characteristic of a double-fed fan by parallel connection grounding admittance; performing two times of contraction treatment on a node voltage equation of the double-fed fan-containing multi-machine system, combining the active and reactive information included in the double-fed fan into an admittance matrix of the synchronous machine nodes, namely, converting the influence of the double-fed fan on the electromagnetic power of the synchronous machine into changes on the electrical relation intensity between the synchronous machines; and performing analysis on the mutual synchronicity of the power angle of the synchronous machine of the multi-machine system and the transient state stability of the multi-machine system with wind power plant access, according to the contraction treatment result by combination with a node injection current formula and an expansion equal-area criterion.

Description

technical field [0001] The invention relates to the field of transient stability analysis of power systems, in particular to a method for analyzing transient power angle stability of a multi-machine system including a wind farm. Background technique [0002] Wind power generation is one of the main means to solve the energy crisis and environmental problems at present. my country's wind power industry has developed extremely rapidly, and the total installed capacity has continued to increase. The large-scale connection of wind farms has a great impact on the original transient stability of the power system. It is necessary to conduct theoretical analysis and research on the transient stability of power systems including wind farms. [0003] At present, there have been many studies on the influence of wind farms on the transient stability of power systems, and some achievements have been made. Based on the time-domain simulation analysis method, the main researches involved...

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Problems solved by technology

[0006] (1) Most of the existing research aims to compare the power angle stability of the synchronous machine before and after the wind farm is connected. In essence, it regards the wind farm as a device with fixed output characteristics to analyze the impact of its connection on system stability. However, the impact of the transient response change characteristics of the wind turbine during the fault period on the power angle of the synchronous machine is not fully considered;

[0007] (2) At present, the research is mainly on single-machine infinite or equivalent double-machine systems, but the actual power system is mostly composed of multiple synchronous machines, and the stability analysis mainly depends on the power angle mutual synchronization between the synchronous machines. Taking single-machine or double-machine system as the research object will not be able to truly reflect the stability between the synchronous machines of the actual multi-machine system, so it is more practical to study the stability analysis method of the multi-machine system including wind farms;

[0008] (3) Wind turbines are required to have low-voltage ride-through (LVRT) capability. Wind turbines with different LVRT measures have different transient responses during faults, and the impact on the electromagnetic power and power angle of the synchronous machine will also change accordingly. Some studies did not consider the transient response changes of DFIG during faults

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