Doubly-fed fan grid-connected system oscillation analysis method based on Nyquist stability criterion

A technology of oscillation analysis and double-fed fan, applied in the direction of single-network parallel feeding arrangement, etc., can solve the problems of calculation difficulties, dimension disaster, and the inability to accurately reveal the coupling effect of units, and achieve the effect of solving calculation difficulties

Pending Publication Date: 2020-04-14
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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Problems solved by technology

[0002] Most of the existing field-level impedance network models directly follow the topological structure of the wind farm, and the entire wind farm is equivalent to one or several units of the same type (impedance compon...

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  • Doubly-fed fan grid-connected system oscillation analysis method based on Nyquist stability criterion
  • Doubly-fed fan grid-connected system oscillation analysis method based on Nyquist stability criterion
  • Doubly-fed fan grid-connected system oscillation analysis method based on Nyquist stability criterion

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Embodiment Construction

[0021] The preferred embodiments will be described in detail below in conjunction with the accompanying drawings.

[0022] Based on the existing field-level modeling method and impedance network model analysis method, the present invention applies the idea of ​​frequency domain transfer function to wind farm impedance network modeling. figure 1 Taking the two-machine system shown as an example, the impedance network modeling method of the doubly-fed wind power multi-machine grid-connected system is introduced.

[0023] Schematic diagram of the structure of the two-machine grid-connected system established by the present invention is as follows figure 1 As shown, the impedance models of the two wind turbines G1 and G2 at different positions in the figure are Z G1 ,Z G2 (Z G1 ≠ Z G2 ), first transform Z through the box respectively T1 ,Z T2 (Z T1 ≠ Z T2 ) boost, and then through the power line Z l1 ,Z l2 (Z l1 l2 , G1 is the remote unit, G2 is the near-end unit) conne...

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Abstract

The invention belongs to the technical field of wind power generation, and particularly relates to a doubly-fed fan grid-connected system oscillation analysis method based on a Nyquist stability criterion. The method comprises the following steps: establishing a multi-machine grid-connected structure, enabling each DFIG to be equivalent to a current source, and establishing a multi-machine grid-connected system impedance network model; listing and writing a system voltage equation and a current equation according to the multi-machine grid-connected system impedance network model; converting the equation into a frequency domain equation to obtain a system open-loop transfer function; and carrying out oscillation analysis on the open-loop transfer function by utilizing the Nyquist stabilitycriterion to obtain a result. The method for analyzing an oscillation mechanism by utilizing the frequency domain Nyquist stability criterion comprises the following steps: determining a resonant frequency according to an intersection point of a semi-closed curve of the open-loop transfer function and a unit circle; judging a wind turbine generator acting on resonance according to a distance between the intersection point and a point (-1, j0); and determining a phase angle margin of resonance.

Description

technical field [0001] The invention belongs to the technical field of wind power generation, and in particular relates to an oscillation analysis method of a doubly-fed fan grid-connected system based on the Nyquist stability criterion. Background technique [0002] Most of the existing field-level impedance network models directly follow the topological structure of the wind farm, and the entire wind farm is equivalent to one or several units of the same type (impedance components), or an interconnected closed-loop system. Both of them are easy to bring the "curse of dimensionality" problem that is difficult to calculate, and the latter cannot accurately reveal the coupling effect between units. Contents of the invention [0003] In order to solve the above problems, the present invention proposes a method for analyzing the oscillation of a doubly-fed fan grid-connected system based on the Nyquist stability criterion, including: [0004] Step 1, establish a multi-machin...

Claims

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Application Information

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IPC IPC(8): H02J3/38
Inventor 刘其辉高瑜逄思敏洪晨威
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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