Groundwall insulation damage localization of large generator stator bar using an active Lamb waves method

Li, Ruihua; Li, Hao; Hu, Bo; Guo, Qi

doi:10.1109/tdei.2017.005742

Cited by 13 publications

(4 citation statements)

References 28 publications

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“…Large-capacity wind power generation units are the future development trend, and DFIG is currently the mainstream model of land wind power. The stator winding is the key component of the generator [1], and the stator winding insulation is one of the most vulnerable parts of the generator [2]. In addition to normal aging factors, the vibration wear of the winding is an important factor that damages the stator winding of the generator [3,4].…”

Section: Introductionmentioning

confidence: 99%

Impact of Radial Air-Gap Eccentricity on Stator End Winding Vibration Characteristics in DFIG

Zhang

et al. 2022

Energies

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In this paper, qualitative theoretical derivations, finite element analysis (FEA) and experiments are used to investigate the electromagnetic force (EF) and vibration characteristics of end windings. In contrast to previous studies, this study focuses not only on end winding EF/vibration under normal and radial static air gap eccentricity (RSAGE) conditions, but also for the cases of radial dynamic air gap eccentricity (RDAGE) and radial dynamic static hybrid air gap eccentricity (RHAGE). Firstly, the magnetic flux density (MFD) is derived for normal and radial air gap eccentricity (RAGE) faults, and detailed EF expressions are obtained before and after the RAGE fault. The finite element analysis (FEA) and experimental studies were performed on a four-pole DFIG at a speed of 1500 rpm to verify the proposed theoretical analysis. It is shown that RSAGE only enlarges the EF/end winding vibration and does not introduce new frequency components. RDAGE not only increases EF/end winding vibration but also introduces new frequency components. RHAGE can be seen as a superimposed effect of RSAGE and RDAGE.

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Section: Introductionmentioning

confidence: 99%

Impact of Radial Air-Gap Eccentricity on Stator End Winding Vibration Characteristics in DFIG

Zhang

et al. 2022

Energies

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“…Structural health monitoring (SHM) [ 6 ] has been employed for internal or surface damage detection in real time and early diagnosis and prediction, ultimately to avoid catastrophic accidents. A Lamb wave, which is a type of wave propagating in a plate-like structure, can be utilized to detect small damages in composite structures; Lamb waves have been applied to detect and locate stator insulation damage [ 7 , 8 , 9 ]. The multi-mode and dispersion characteristics of Lamb wave propagation, particularly in the laminated stator insulation composite structure of large generators, deteriorate the signal-to-noise ratio (SNR) and resolution of the sensing signal.…”

Section: Introductionmentioning

confidence: 99%

“…To locate the damage in a stator insulation structure, it is important to accurately extract the time of flight (TOF) features of the Lamb wave [ 9 , 16 ]. The multi-mode and dispersion characteristics of Lamb waves during propagation can hinder the extraction of TOF features.…”

Section: Introductionmentioning

confidence: 99%

“…Li et al [ 8 ] used the Hilbert transform to extract TOF features, albeit with a low location accuracy. A TOF extraction method based on the Hilbert cross-correlation coefficient was proposed in [ 9 ]. Although this method has a higher location accuracy than the Hilbert method, the TOF feature extraction ability under strong background noise is poor, thus limiting its practical applications.…”

Section: Introductionmentioning

confidence: 99%

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Lamb Wave-Based Damage Localization Feature Enhancement and Extraction Method for Stator Insulation of Large Generators Using VMD and Wavelet Transform

Luo

2020

Sensors

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Lamb waves are used to locate any damage in the stator insulation structure of large generators. However, it is difficult to extract the features of Lamb wave signals in a strong background noise environment, thus significantly reducing the accuracy with which the damage is located. This paper proposes a method based on variational mode decomposition (VMD) and wavelet transform to enhance and extract the location features of stator insulation damage signals of large motors. First, considering that the characteristics of VMD are sensitive to noise, the Lamb wave detection signal is decomposed, denoised, and reconstructed; the reconstructed signal is then wavelet-transformed to extract the time of flight (TOF) of the damage-scattered wave as the damage location feature; finally, the damage location is determined using the TOF features. The proposed method is experimentally tested and verified under various noise environments. The results show that the VMD and wavelet transform methods can significantly improve the signal-to-noise ratio of Lamb wave detection signals and the accuracy with which the damage is located under strong background noise. This study extends the applicability of Lamb wave-based non-destructive detection of stator insulation damage in complex environments.

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Comprehensive Investigation of Winding Mechanical Properties in Generators under RISC: Impact of Position, Degree, and Eccentricity

Xu,

He,

Zhang

et al. 2024

IEEJ Transactions Elec Engng

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This paper provides an in‐depth study of the winding mechanical properties in generators under rotor interturn short circuit (RISC) cases. Unlike previous studies, this research investigates not only the influence of RISC degrees, but also the RISC positions and the eccentricity on the winding mechanical properties. The electromagnetic force (EF) formulas as well as the electromagnetic‐structure coupling model are first proposed to derive the mechanical winding response characteristics, such as the vibration, deformation, the strain, and the stress. Subsequently, both finite element analysis (FEA) and experimental investigations are conducted to validate the theoretical findings. The results reveal that RISC introduces additional harmonics to the EF. Furthermore, as the eccentricity/RISC degree or the distance between the short circuit position and the N‐pole increases, the end winding vibrations become more pronounced. When comparing single eccentricity and RISC faults to cases where both faults occur simultaneously, it is observed that the combined faults have a more detrimental impact on the end winding mechanical properties. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

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Groundwall insulation damage localization of large generator stator bar using an active Lamb waves method

Cited by 13 publications

References 28 publications

Impact of Radial Air-Gap Eccentricity on Stator End Winding Vibration Characteristics in DFIG

Impact of Radial Air-Gap Eccentricity on Stator End Winding Vibration Characteristics in DFIG

Lamb Wave-Based Damage Localization Feature Enhancement and Extraction Method for Stator Insulation of Large Generators Using VMD and Wavelet Transform

Comprehensive Investigation of Winding Mechanical Properties in Generators under RISC: Impact of Position, Degree, and Eccentricity

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