Damage Identification of Large Generator Stator Insulation Based on PZT Sensor Systems and Hybrid Features of Lamb Waves

Large generators are the principal pieces of equipment in power systems, and their operation reliability critically depends on the stator insulation. Damages in stator insulation will gradually lead to the failure and breakdown of generator. Due to the advantages of Lamb waves in Structural health m...

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Main Authors: Ruihua Li, Hao Li, Bo Hu
Format: Article
Language:English
Published: MDPI AG 2018-08-01
Series:Sensors
Subjects:
Online Access:http://www.mdpi.com/1424-8220/18/9/2745
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author Ruihua Li
Hao Li
Bo Hu
author_facet Ruihua Li
Hao Li
Bo Hu
author_sort Ruihua Li
collection DOAJ
description Large generators are the principal pieces of equipment in power systems, and their operation reliability critically depends on the stator insulation. Damages in stator insulation will gradually lead to the failure and breakdown of generator. Due to the advantages of Lamb waves in Structural health monitoring (SHM), in this study, a distributed piezoelectric (PZT) sensor system and hybrid features of the Lamb waves are introduced to identify stator insulation damage of large generator. A hierarchical probability damage-imaging (PDI) algorithm is proposed to tackle the material inhomogeneity and anisotropy of the stator insulation. The proposed method includes three steps: global detection using correlation coefficients, local detection using Time of flight (ToF) along with the amplitude of damage-scattered Lamb wave, and final images fusion. Wavelet Transform was used to extract the ToF of Lamb wave in terms of the time-frequency domain. Finite Element Modeling (FEM) simulation and experimental work were carried out to identify four typical stator insulation damages for validation, including inner void, inner delamination, puncture, and crack. Results show that the proposed method can precisely identify the location of stator insulation damage, and the reconstruction image can be used to identify the size of stator insulation damage.
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spelling doaj.art-0c819fe0e12443e198f5c8ab13e376c92022-12-22T04:22:16ZengMDPI AGSensors1424-82202018-08-01189274510.3390/s18092745s18092745Damage Identification of Large Generator Stator Insulation Based on PZT Sensor Systems and Hybrid Features of Lamb WavesRuihua Li0Hao Li1Bo Hu2Department of Electrical Engineering, Tongji University, Shanghai 201804, ChinaCollege of Electrical Engineering, Shanghai University of Electrical Power, Shanghai 200090, ChinaDepartment of Electrical Engineering, Tongji University, Shanghai 201804, ChinaLarge generators are the principal pieces of equipment in power systems, and their operation reliability critically depends on the stator insulation. Damages in stator insulation will gradually lead to the failure and breakdown of generator. Due to the advantages of Lamb waves in Structural health monitoring (SHM), in this study, a distributed piezoelectric (PZT) sensor system and hybrid features of the Lamb waves are introduced to identify stator insulation damage of large generator. A hierarchical probability damage-imaging (PDI) algorithm is proposed to tackle the material inhomogeneity and anisotropy of the stator insulation. The proposed method includes three steps: global detection using correlation coefficients, local detection using Time of flight (ToF) along with the amplitude of damage-scattered Lamb wave, and final images fusion. Wavelet Transform was used to extract the ToF of Lamb wave in terms of the time-frequency domain. Finite Element Modeling (FEM) simulation and experimental work were carried out to identify four typical stator insulation damages for validation, including inner void, inner delamination, puncture, and crack. Results show that the proposed method can precisely identify the location of stator insulation damage, and the reconstruction image can be used to identify the size of stator insulation damage.http://www.mdpi.com/1424-8220/18/9/2745rotating machine insulationrotating machine insulation testingcrack detectionacoustic signal processingacoustic applications
spellingShingle Ruihua Li
Hao Li
Bo Hu
Damage Identification of Large Generator Stator Insulation Based on PZT Sensor Systems and Hybrid Features of Lamb Waves
Sensors
rotating machine insulation
rotating machine insulation testing
crack detection
acoustic signal processing
acoustic applications
title Damage Identification of Large Generator Stator Insulation Based on PZT Sensor Systems and Hybrid Features of Lamb Waves
title_full Damage Identification of Large Generator Stator Insulation Based on PZT Sensor Systems and Hybrid Features of Lamb Waves
title_fullStr Damage Identification of Large Generator Stator Insulation Based on PZT Sensor Systems and Hybrid Features of Lamb Waves
title_full_unstemmed Damage Identification of Large Generator Stator Insulation Based on PZT Sensor Systems and Hybrid Features of Lamb Waves
title_short Damage Identification of Large Generator Stator Insulation Based on PZT Sensor Systems and Hybrid Features of Lamb Waves
title_sort damage identification of large generator stator insulation based on pzt sensor systems and hybrid features of lamb waves
topic rotating machine insulation
rotating machine insulation testing
crack detection
acoustic signal processing
acoustic applications
url http://www.mdpi.com/1424-8220/18/9/2745
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AT haoli damageidentificationoflargegeneratorstatorinsulationbasedonpztsensorsystemsandhybridfeaturesoflambwaves
AT bohu damageidentificationoflargegeneratorstatorinsulationbasedonpztsensorsystemsandhybridfeaturesoflambwaves