Structural health monitoring of compression connectors for overhead transmission lines

Hong Wang, Jy An John Wang, Joseph P. Swindeman, Fei Ren, John Chan

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations

Abstract

Two-stage aluminum conductor steel-reinforced (ACSR) compression connectors are extensively used in US overhead transmission lines. The connectors are made by crimping a steel sleeve onto a steel core and an aluminum sleeve over electrical conducting aluminum strands. The connectors are designed to operate at temperatures up to 125°C, but their performance is increasingly degrading because of overloading of lines. Currently, electric utilities conduct routine line inspections using thermal and electrical measurements, but these methods do not provide information about the structural integrity of connectors. In this work, structural health monitoring (SHM) of compression connectors was studied using electromechanical impedance (EMI) analysis. Lead zirconate titanate (PZT)-5A was identified as a smart material for SHM. A flexible high-temperature bonding layer was used to address challenges in PZT integration due to a significant difference in the coefficients of thermal expansion of PZT and the aluminum substrate. The steel joint on the steel core was investigated because it is responsible for the ultimate tensile strength of the connector. Tensile testing was used to induce structural damage to the joint, or steel core pullout, and thermal cycling introduced additional structural perturbations. EMI measurements were conducted between the tests. The root mean square deviation (RMSD) of EMI was identified as a damage index. The use of steel joints has been shown to enable SHM under simulated conditions. The EMI signature is sensitive to variations in structural conditions. RMSD can be correlated to the structural health of a connector and has potential for use in the SHM and structural integrity evaluation.

Original languageEnglish
Title of host publicationNondestructive Characterization and Monitoring of Advanced Materials, Aerospace, and Civil Infrastructure 2017
EditorsTzu-Yang Yu, H. Felix Wu, Peter J. Shull, Andrew L. Gyekenyesi
PublisherSPIE
ISBN (Electronic)9781510608238
DOIs
StatePublished - 2017
EventConference on Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, Civil Infrastructure, and Transportation XI 2017 - Portland, United States
Duration: Mar 26 2017Mar 29 2017

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume10169
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

ConferenceConference on Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, Civil Infrastructure, and Transportation XI 2017
Country/TerritoryUnited States
CityPortland
Period03/26/1703/29/17

Keywords

  • Compression connectors
  • Damage index
  • Electromechanical impedance
  • PZT
  • Structural health monitoring
  • Transmission lines

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