Fault diagnosis method for three-phase unsymmetrical loads of doubly-fed wind turbine rotor windings

Abstract

The invention discloses a double-fed wind generator rotor winding three-phase asymmetric load fault diagnosis method which includes the steps: 1 building a double-fed wind generator rotor winding fault simulation system on a dynamic simulation experiment platform; 2 acquiring rotor current or voltage signals on a rotor side before and after fault in different running states of a motor, correspondingly recording waves by a fault wave recording analysis device, reading data by a MATLAB (matrix laboratory), filtering direct current components and performing FFT (fast Fourier transform) processing; 3 extracting obviously changed frequency serving as fault diagnosis characteristic frequency before and after fault according to amplitude change to judge whether a double-fed wind generator rotor winding has three-phase asymmetric load faults or not. Diagnosis results are quite approximate to true values and effective, diagnosis accuracy is high, and operability is strong.

Description

Technical field [0001] The invention relates to a three-phase asymmetric load fault diagnosis method for the rotor winding of a doubly-fed wind generator, belonging to the technical field of drive motor state detection and fault diagnosis. Background technique [0002] The normal operation of the generator is of great significance to the safety and stability of the entire power grid. In wind farms, doubly-fed wind turbines have become mainstream models due to their high efficiency, low cost, and adjustable power factor. Due to the harsh operating environment, wind turbines cause far more failures than conventional generators. Therefore, in order to enhance the reliability of wind turbines, and to carry out early warning and timely maintenance of faults, the research on the online monitoring technology of wind turbines is very important. [0003] Due to its own external circuit and a back-to-back converter connected to the rotor winding of the doubly-fed wind generator, it is diff...

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Problems solved by technology

The domestic research is relatively mature, and the literature can use the corresponding characteristic method to select the appropriate characteristic signal to find the fault; Yazidi A, a scholar from the University of Picardie in France, established a model for the normal and inter-turn short circuit of the double-fed wind turbine for the circuit to conduct simulation research; Scholars Dinkhauser V of the University of Kiel in Germany used MATLAB software to establish a doubly-fed motor model, introduced the factor u to characterize the severity of inter-turn faults, and searched for fault characteristics through wavelet analysis and Lomberg observers; Scholars Gritli Y of the University of Bologna in Italy studied the rotor winding The experimental data of the fault is analyzed, the fault is quantified by wavelet transform, and the fixed threshold is set to judge the fault, but the influence of different control strategies of the rotor converter on the extraction of the characteristic signal is not considered

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