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Dynamic energy stability evaluating method and system for doubly-fed induction generator grid-connected system

A technology of doubly-fed wind turbines and system dynamics, which is applied in wind power generation, electricity measurement, measurement devices, etc., can solve the problems of low accuracy of stability evaluation, and achieve the guarantee of operation stability and safety, small calculation amount, and adjustment process. quick effect

Active Publication Date: 2019-10-18
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of the above analysis, the present invention aims to provide a method and system for evaluating the dynamic energy stability of a doubly-fed wind turbine grid-connected system to solve the problem of low stability assessment accuracy of the existing wind turbine grid-connected system

Method used

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  • Dynamic energy stability evaluating method and system for doubly-fed induction generator grid-connected system
  • Dynamic energy stability evaluating method and system for doubly-fed induction generator grid-connected system
  • Dynamic energy stability evaluating method and system for doubly-fed induction generator grid-connected system

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Embodiment 1

[0050] Embodiment 1 of the present invention discloses a method for evaluating the dynamic energy stability of a doubly-fed fan grid-connected system, the schematic diagram is as follows figure 1 As shown, the steps are as follows:

[0051] Step S1: When sub-synchronous oscillation occurs in the double-fed wind turbine grid-connected system, collect the instantaneous values ​​of voltage and current at the grid-connected point of the wind turbine and the series compensation point;

[0052] Preferably, in step S1, whether subsynchronous oscillation occurs in the doubly-fed wind turbine grid-connected system is detected by the following method: real-time collection of the current at the grid-connected point of the wind turbine, if the current frequency at the grid-connected point of the wind turbine is within the sub-synchronous oscillation frequency range , it is determined that subsynchronous oscillation occurs in the double-fed wind turbine grid-connected system; preferably, t...

Embodiment 2

[0092] In embodiment 2 of the present invention, as figure 2 The equivalent wind farm connected to the grid through series compensation is shown as an example. The equivalent model of double-fed wind turbine parallel connection is used to simulate the wind farm, and the simulation model is built on the Matlab / Simulink platform. The wind farm is composed of 100 identical doubly-fed wind turbines connected in parallel. After the outlets of the wind turbines are connected in parallel, they supply power to the grid through the busbar. The rated capacity of each wind turbine is 1.5MW, and they operate according to the rated output. The wind turbines adopt the generator practice. The subsynchronous oscillation of the wind turbine grid-connected system is induced by changing the grid-connected parameters of the doubly-fed wind turbine, so as to verify the dynamic energy of the wind turbine. The parameters of DFIG are shown in Table 1.

[0093] Table 1 Parameters of DFIG

[0094] ...

Embodiment 3

[0117] Embodiment 3 of the present invention discloses a dynamic energy stability evaluation system of a doubly-fed fan grid-connected system, such as Figure 12 As shown, it includes: a data acquisition module, used to collect the instantaneous values ​​of voltage and current at the grid-connected point of the fan and the series compensation place when the sub-synchronous oscillation occurs in the doubly-fed fan grid-connected system; a dynamic energy acquisition module, used to The instantaneous value of the voltage and current at the wind turbine grid-connected point and the series compensation point output by the collection module is used to obtain the dynamic energy of the double-fed wind turbine grid-connected system; the aperiodic component extraction module is used to collect the integer-period double-fed wind turbine grid-connected system. Dynamic energy, from which the non-periodic component is extracted; the stability evaluation module is used to analyze the rate of ...

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Abstract

The invention relates to a dynamic energy stability evaluating method and system for a doubly-fed induction generator grid-connected system and belongs to the technical field of wind power generationsystems. With the dynamic energy stability evaluating method and system for the doubly-fed induction generator grid-connected system of the invention adopted, the problem of the low accuracy of the stability evaluation of an existing wind turbine generator grid-connected system can be solved. The method comprises the following steps that: when secondary synchronous oscillation occurs on the doubly-fed induction generator grid-connected system, the voltage and current instantaneous values of an induction generator grid-connected point and a series compensation position are acquired; the dynamicenergy of the doubly-fed induction generator grid-connected system is obtained based on the voltage and current instantaneous values of the induction generator grid-connected point and the series compensation position; the dynamic energy of the doubly-fed induction generator grid-connected system in integer periods is collected, and non-periodic components are extracted from the dynamic energy; and if the change rate of the non-periodic components is positive, the doubly-fed induction generator grid-connected system has a negative damping characteristic, and oscillation diverges, and otherwise, the doubly-fed induction generator grid-connected system has a positive damping characteristic, and oscillation converges. With the method and system of the invention adopted, the stability of thedoubly-fed induction generator grid-connected system can be accurately and effectively evaluated.

Description

technical field [0001] The invention relates to the technical field of wind power generation systems, in particular to a method and system for evaluating dynamic energy stability of a doubly-fed wind turbine grid-connected system. Background technique [0002] In recent years, with the rapid increase of the access capacity of wind turbines, the dynamic characteristics of modern power grids have changed, and the new subsynchronous oscillation problem has become prominent. In October 2009, an oscillation accident occurred in a doubly-fed wind farm in Texas, USA, causing a large number of units to go off-grid. After analysis, the cause of the accident was the mutual boosting oscillation between the machine-side converter of the doubly-fed wind turbine and the series compensation on the transmission line. This type of oscillation appeared for the first time. In recent years, there have been many similar subsynchronous oscillation accidents in China, including the Guyuan subsync...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38G06F17/50G06Q10/06G06Q50/06G01R31/00
CPCH02J3/386G06Q10/0639G06Q50/06G01R31/00G06F30/367H02J2203/20Y02P90/82Y02E10/76
Inventor 马静杨更宇张嘉鑫李沛
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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