Transient stability evaluation method and device for doubly-fed fan

By establishing the amplitude phase model of the double-feeding fan and calculating the work angle convergence evaluation value, the problem of difficulty in accurately evaluating the transient stability of DFIG in the prior art is solved, the accuracy and convenience of evaluation are improved, and the stability of DFIG under weak grid conditions is enhanced.

CN119695955APending Publication Date: 2025-03-25ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID JIBEI ELECTRIC POWER CO LTD +1
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Patent Information

Application Number
CN202411706259.8
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2024-11-26
Publication Date
2025-03-25

AI Technical Summary

Technical Problem

It is difficult for the prior art to accurately evaluate the transient stability of double-feed induction generators (DFIGs). Especially in wind power iongrid scenarios, existing small signal analysis methods ignore the nonlinear characteristics of the system, while nonlinear large signal analysis methods are computationally expensive and lack clear instability criteria.

Method used

By establishing the amplitude phase model of the double-feed fan, the relationship between the rotor straight-axis current and the work angle is obtained, and the stable equilibrium point and unstable equilibrium point are determined based on the intersection of the mechanical power curve and the electromagnetic power curve. If the evaluation value of the power angle convergence is less than or equal to zero, it is judged that the double-feed fan is in transient stable state.

Benefits of technology

It improves the accuracy and convenience of the transient stability evaluation of double-feeding fans, avoids the high-order complexity in traditional methods, is suitable for different low-voltage crossing control strategies, and enhances the stability and operating efficiency of DFIG under weak grid conditions.

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Abstract

The invention provides a transient stability evaluation method and device for a doubly-fed fan, and the method comprises the steps: obtaining a relation between a direct-axis current of a rotor and a power angle according to an evaluation parameter of the doubly-fed fan and an amplitude-phase model of the doubly-fed fan; if the existence of a stable equilibrium point and an unstable equilibrium point is determined according to the power angle corresponding to the intersection point of the mechanical power curve and the electromagnetic power curve, obtaining a power angle convergence evaluation value according to the initial value of the power angle, the power angle corresponding to the unstable equilibrium point, the mechanical power curve and the electromagnetic power curve; wherein the mechanical power curve is established on the basis of the relation between the direct-axis current of the rotor and the power angle, and the electromagnetic power curve is established on the basis of the power angle and the common connection point voltage included in the evaluation parameters; and if the power angle convergence evaluation value is judged to be less than or equal to zero, determining that the doubly-fed fan is in transient stability. According to the transient stability evaluation method and device for the doubly-fed wind turbine, the accuracy and convenience of transient stability evaluation of the doubly-fed wind turbine are improved.
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