Ultra-low frequency oscillation inhibition method based on root locus group

A root locus family, ultra-low frequency technology, applied in the direction of reducing/preventing power oscillation, reducing flicker of AC network, AC network circuit, etc., to achieve good suppression effect, clear mathematical foundation, and weaken the effect of negative damping effect

CN110224416AActive Publication Date: 2019-09-10SOUTHWEST JIAOTONG UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2019-09-10

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Abstract

The invention discloses an ultra-low frequency oscillation inhibition method based on root locus group. The method comprises the following steps of S1, constructing a detailed model of a hydroelectricgeneration system; S2, carrying out derivation to obtain an analysis expression of the damping torque coefficient of an original moving system; S3, analyzing the influence of the damping torque coefficient on system damping; S4, analyzing the influence of PID parameters of a speed regulator on the damping torque coefficient; S5, constructing a two-machine equivalent system model, drawing a systemroot locus group to obtain the position of a dominant pole of a system generating ultralow frequency oscillation on the root locus group, and determining the PI parameter range of the speed regulatorwhen the system is stable; S6, according to an introduced equal-damping ratio line, determining an ideal reset point of the dominant pole, and replacing the PI parameter value of the speed regulatorcorresponding to the rest point with the original PI parameter value of the speed regulator, optimizing the parameters of the speed regulator and suppressing ultra-low frequency oscillation; and S7, based on the PSD-BPA software, performing off-line simulation on a power grid large system, analyzing the ultralow-frequency oscillation problem and verifying the correctness of the extraction method.
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Description

technical field

[0001] The invention belongs to the technical field of power systems, and in particular relates to a method for suppressing ultra-low frequency oscillation based on root locus family. Background technique

[0002] In 2016, during the verification experiment of asynchronous networking between Yunnan and the southern main grid, the Yunnan power grid experienced continuous oscillation with an oscillation frequency lower than 0.1 Hz, that is, ultra-low frequency oscillation. Ultra-low frequency oscillation is different from traditional low-frequency oscillation. It is a coherent oscillation of the entire network caused by small disturbances in the frequency adjustment process, and belongs to the category of frequency stability. As early as the 1960s and 1970s, the Canadian power grid had ultra-low frequency oscillations, and some scholars conducted basic theoretical research on this phenomenon. In recent years, ultra-low frequency oscillations with a frequency l...

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Embodiment Construction

[0069] The specific embodiments of the present invention are described below so that those skilled in the art can understand the present invention, but it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes Within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are included in the protection list.

[0070] According to an embodiment of the present application, refer to Figure 14 , the ultra-low frequency oscillation suppression method based on the root locus family of this scheme, including:

[0071] S1. Construct a detailed model of the hydroelectric power generation system, and obtain the transfer function of the prime mover system according to the detailed model;

[0072] S2, based on the damping torque method, de...