An online fault diagnosis method for blade unbalance of doubly-fed wind turbine

Abstract

The invention provides a blade imbalance on-line fault diagnosis method of a doubly-fed wind generator. The method comprises the steps that the rotating speed of the doubly-fed wind generator and the power signal P output by the generator are synchronously sampled; the input pneumatic torque T of a fan hub is estimated according to the rotational inertia J of the fan hub and the generator output power and the rotating speed which are synchronous sampled in the sampling period; order analysis is conducted to obtain a resampled pneumatic torque Ta, and the frequency fuzzy phenomenon caused by rotating speed variation is removed; power spectrum analysis is conducted on the signals after order analysis and reconstitution, and feature extraction is conducted; a frequency doubling power spectrum amplitude Q(1) and a frequency tripling power spectrum amplitude Q(3) are compared, and if Q(1) is larger than Q(3), it is judged that an imbalance fault happen. According to the blade imbalance on-line fault diagnosis method of the doubly-fed wind generator, the blade imbalance fault of the doubly-fed wind generator is judged according to the synchronously-sampled signals of the rotating speed, the voltages and the currents of the doubly-fed wind generator, and safe and normal working of a wind generating set is guaranteed. A used sensor is simple, convenient to mount and very suitable for field service.

Description

technical field [0001] The invention relates to an online fault diagnosis method for blade unbalance of a doubly-fed wind power generator, belonging to the technical field of wind power generation. Background technique [0002] Significance of wind power——Wind power is a kind of renewable green energy that the country advocates to vigorously develop. It can effectively save water and coal resources, reduce air pollution, and has far-reaching significance for protecting the ecological environment. my country has abundant wind power resources, and the government has taken wind power generation as one of the main alternative energy technologies to improve energy structure, cope with climate change, and improve energy security. It is estimated that by 2020, more than 10% of the world's electricity supply will come from wind power. Compared with thermal power and nuclear power, wind power has a small unit capacity and covers a large area. Wind farms are usually located in remote...

AI Technical Summary

Problems solved by technology

The above-mentioned patents basically use video, strain gauge, sound and other methods to detect whether the blade has a serious fault. These methods are either complicated to install and not suitable for online fault diagnosis, or the detection accuracy is not high, and it is difficult to detect non-serious blade faults.

"Blade Unbalance Fault Diagnosis Method of Wind Turbine Based on Current Signal" (201210396295.X) uses the three-phase current signal of the generator to extract the fluctuating frequency signal for blade unbalance fault diagnosis. The unbalanced fault of the blades of the driving fan, but for the doubly-fed unit due to the excitation control, the output signal fluctuation of the generator will be greatly reduced, and it is difficult to directly use this signal for fault diagnosis

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