Advanced Inspection Advanced Inspection Techniques for Monitoring Techniques for Monitoring

Cable AgingCable Aging

Module 3Module 3

Dr. John H. BickelDr. John H. BickelEvergreen Safety & Reliability Technologies, LLCEvergreen Safety & Reliability Technologies, LLC

Two Types of Inspection Techniques Two Types of Inspection Techniques for Monitoring Cable Agingfor Monitoring Cable Aging

In-situ or Non-destructive MethodsIn-situ or Non-destructive Methods

Methods requiring removal of cableMethods requiring removal of cable

Time Delay ReflectrometryTime Delay ReflectrometryTDR works similar to RADARTDR works similar to RADARTDR pulse is injected to length of cableTDR pulse is injected to length of cableReflections generated at points of changes Reflections generated at points of changes

in Impedancein ImpedanceTDR historically used for transmission TDR historically used for transmission

system cable to determine moisture system cable to determine moisture buildup in cablebuildup in cable

TDR can identify problems with local TDR can identify problems with local materials breakdown, connector corrosionmaterials breakdown, connector corrosion

Time Delay ReflectrometryTime Delay Reflectrometry

Time Delay ReflectrometryTime Delay Reflectrometry

Time Delay ReflectrometryTime Delay Reflectrometry

Time Delay ReflectrometryTime Delay Reflectrometry

TDR BenefitsTDR BenefitsTDR successfully used in many types of TDR successfully used in many types of

cables and cable geometries.cables and cable geometries.TDR has found: cracking in insulation, TDR has found: cracking in insulation,

corrosion, water intrusion, poor electrical corrosion, water intrusion, poor electrical connectionsconnections

TDR can identify location of major change TDR can identify location of major change in Impedence – which requires further in Impedence – which requires further investigation.investigation.

Microscopy TechniquesMicroscopy TechniquesScanning Acoustic MicroscopeScanning Acoustic MicroscopeScanning Electron MicroscopeScanning Electron MicroscopeBoth require representative samples of Both require representative samples of

cable materialscable materialsPrimarily used to determine average Primarily used to determine average

insulation void content, void sizeinsulation void content, void size

Scanning Acoustic MicroscopyScanning Acoustic Microscopy

Scanning Acoustic MicroscopyScanning Acoustic Microscopy

Scanning Electron MicroscopyScanning Electron Microscopy

MicroscopyMicroscopyMicroscopy has been very useful in Microscopy has been very useful in

identifying mechanisms for aging related identifying mechanisms for aging related degradation.degradation.

Microscopy identified the role of gas Microscopy identified the role of gas pocket buildup in insulation layer as pocket buildup in insulation layer as mechanism of degradation. mechanism of degradation.

Not easily used for determination of Not easily used for determination of residual life.residual life.