Small-interference stability modal analysis method of double-fed wind generator one-machine infinite system

A technology of doubly-fed wind turbines and analysis methods, applied in wind power generation, single-network parallel feeding arrangements, instruments, etc., can solve problems such as no detailed establishment, no system mode impact research, etc., to improve accuracy and comprehensiveness Effect

CN110212575APending Publication Date: 2019-09-06GUIZHOU POWER GRID CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2019-09-06

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Abstract

The invention discloses a small-interference stability analysis method of a double-fed wind generator one-machine infinite system; the method comprises the following steps of step 1, modeling a dynamic mathematical model of the one-machine infinite system; step 2, performing linearization processing on the mathematical model of the system at the balance point to obtain a corresponding state matrix; step 3, obtaining a system characteristic value and a mode category, and predicting a state variable and a modal relationship according to participation factors; and step 4, according to system parameters or running states and external network parameters, calculating he sizes and the modal changes of different characteristic values. In the prior art, the technical problems that when the stability of the grid-connected system of the wind generator is researched, the model of some elements in the system, such as a transmission system model and a model of a control system, are not established in detail; and the influence of parameters in the system on the system model state in a detailed model are not researched and the like, are avoided.
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Description

technical field

[0001] The invention belongs to the double-fed fan single-machine infinite system technology, and in particular relates to a small disturbance stability modal analysis method of a double-fed fan single-machine infinite system. Background technique

[0002] Due to the increasing energy shortage and environmental pollution caused by the steady growth of global energy consumption in recent decades, new energy power generation, especially wind power generation, has received more and more attention and played an increasingly important role in the power system. . Due to the randomness of wind energy and the uncertainty of connecting to the grid, the research on the stability of wind turbines connected to the grid has gradually become a focus. For the stability of the wind turbine grid-connected system, it must first be guaranteed to be stable with small disturbances. Therefore, many scholars have studied the stability of the wind turbine grid-connected system. So...

Examples

specific Embodiment

[0084] Unify the mathematical model of the system as a series of differential-algebraic equations g(x,y)=0. Among them, x and y are the state variables and algebraic variables of the system respectively; f and g are differential equations and algebraic equations respectively. Ignoring the second-order and above infinitesimal quantities of the Taylor series, the state-space equation of the system can be expressed as

[0085]

[0086] make Then the state space is

[0087]

[0088] Eliminate Δy to get

[0089]

[0090] Among them, the matrix Often referred to as the coefficient matrix or the state matrix. By studying the state matrix The eigenvalues ​​of The dynamic process of the system can be analyzed. In general, let the generator terminal voltage be 1p.u., the active power be 1p.u., and the speed be the rated synchronous speed. Assuming that the double-fed fan DFIG is directly connected to the infinite bus, the reactive power output is 0, and the termina...