Imbalance Fault Classification Based on VMD Denoising and S-LDA for Variable-Speed Marine Current Turbine

Abstract

Marine current energy as a kind of renewable energy has gradually attracted more and more attention from many countries. However, the blade imbalance fault of marine current turbines (MCTs) will have an effect on the power production efficiency and cause damage to the MCT system. It is hard to classify the severity of an MCT blade imbalance fault under the condition of the current instability and seafloor noise. This paper proposes a fault classification method based on the combination of variational mode decomposition denoising (VMD denoising) and screening linear discriminant analysis (S-LDA). The proposed method consists of three parts. Firstly, phase demodulation of the collected stator current signal is performed by the Hilbert transform (HT) method. Then, the obtained demodulation signal is denoised by variational mode decomposition denoising (VMD denoising), and the denoised signal is analyzed by power spectral density (PSD). Finally, S-LDA is employed on the power signal to determine the severities of fault classification. The effectiveness of the proposed method is verified by experimental results under different severities of blade imbalance fault. The stator current signatures of experiments with different severities of blade imbalance fault are used to validate the effectiveness of the proposed method. The fault classification accuracy is 92.04% based on the proposed method. Moreover, the experimental results verify that the influence of velocity fluctuation on fault classification can be eliminated.

Residual Current Detection Method Based on Variational Modal Decomposition and Dynamic Fuzzy Neural Network

“…The SNR was 10 dB, 15 dB, and 25 dB, respectively. The formula for calculating the SNR is shown in (16).…”

“…However, in practical applications, the residual current signal usually contains noise, which can cause serious interference to the detection. Considering that VMD is sensitive to noise and overcomes the shortcomings of EMD, such as the endpoint effect and false component, the VMD is used to preprocess the residual current signal [16]. However, the number of VMD decomposition levels K needs to be determined in advance, so we proposed the concept and selection method of the general K -value.…”

Identification of fumigated and dyedLycium barbarumby hyperspectral imaging technology

“…In the VMD algorithm, the modal parameter k would affect the decomposition result (Wei et al, 2021). If the k value was too small, it would result in under-decomposition and the original spectrum would be filtered and lost.…”

A Mini Review of Research on Blade Fault Detection of Marine Current Turbine

“…The fault diagnosis method based on stator current (current flowing in the electrical generator) has attracted more and more attention in recent years due to its advantages of non-invasiveness and easy access [15]. In the fault diagnosis of MCTs, the core idea of this method is that when the MCT components failure, the amplitude of certain specific frequency components in the stator current will appear or increase due to the occurrence of the fault, which is called fault indicators.…”