Double-fed grid-connected system subsynchronous oscillation analysis method by considering frequency coupling effect

A technology of sub-synchronous oscillation and coupling effect, applied in the direction of reducing/preventing power oscillation, single-net parallel feeding arrangement, AC network to reduce harmonic/ripple, etc., can solve problems such as synchronous oscillation

Active Publication Date: 2020-08-11
XIAN THERMAL POWER RES INST CO LTD +1
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Problems solved by technology

However, due to the particularity of the control and structure of the doubly-fed wind turbine, this large-scale, long-distance, point-to-network transmission of power through the series compensation line may cause another stability problem - subsynchronous oscillation

Method used

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  • Double-fed grid-connected system subsynchronous oscillation analysis method by considering frequency coupling effect
  • Double-fed grid-connected system subsynchronous oscillation analysis method by considering frequency coupling effect
  • Double-fed grid-connected system subsynchronous oscillation analysis method by considering frequency coupling effect

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Embodiment Construction

[0086] The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

[0087] Such as figure 1 As shown, the present invention is a double-fed grid-connected system subsynchronous oscillation analysis method considering the frequency coupling effect, comprising the following steps:

[0088] Step 1: Enter DFIG fan parameters

[0089] Obtain the following parameters of the DFIG grid-connected system, including: Wind turbine grid-connected voltage V 1 , PLL PI parameter K pp , K pi , Rotor-side converter current inner loop PI parameter K p , K i , K d , fan running shaft frequency ω r , Transmission system resistance R L , inductance L L , Transformer inductance L T , Series compensation capacitor C L .

[0090] Step 2: Establish an analytical model of the external impedance of the doubly-fed fan

[0091] Grid-connected double-fed wind turbine mainly includes induction motor, rotor-side converter, phase...

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Abstract

The invention relates to a double-fed grid-connected system subsynchronous oscillation analysis method by considering a frequency coupling effect. The method comprises the following steps of: firstly,inputting the fan parameter, the operation state and the grid-connected parameter of the doubly-fed grid-connected system; and establishing a doubly-fed fan external impedance analytical model basedon a harmonic linearization method. The method is mainly characterized in that the frequency coupling effect of output harmonic current of the doubly-fed fan under single-frequency harmonic voltage disturbance is considered, and meanwhile, according to two operating states of the doubly-fed fan, the external impedance analytical model of the fan is derived under different operating states; a polecriterion expression suitable for the characteristic equation of the doubly-fed grid-connected system is given in combination with grid-connected parameters; and finally, the subsynchronous oscillation stability of the target is judged system according to the calculated poles of the system characteristic equation. The subsynchronous oscillation mechanism of the doubly-fed grid-connected system isdisclosed quantitatively, and the subsynchronous oscillation stability of the target doubly-fed grid-connected system can be quantitatively analyzed.

Description

technical field [0001] The invention belongs to the field of power systems, relates to the field of stability analysis of double-fed wind turbine grid-connected systems, and in particular relates to a method for analyzing subsynchronous oscillations of double-fed grid-connected systems considering frequency coupling effects. Background technique [0002] The proportion of new energy access to the system is gradually increasing, which brings new challenges to the safe and stable operation of the power system, including stability issues such as subsynchronous oscillation. At present, doubly-fed wind turbines have been widely used in the field of new energy power generation, and doubly-fed wind farms have become the main way to realize large-scale development and utilization of wind energy. When doubly fed wind farms are connected to the grid to transmit power, the series compensation technology of transmission lines is often used to shorten the electrical distance, improve the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J3/24H02J3/01
CPCH02J3/24H02J3/01Y02E40/40
Inventor 舒进张涛都劲松杨俊牛坤蒋昊马晋辉蒋成文王靖程乔越
Owner XIAN THERMAL POWER RES INST CO LTD
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