Reflectometry-based insulation moisture/leak and corrosion detection system.

Reflectometry-based insulation moisture/leak and corrosion detection system

System concept

• Insulation humidity / leak detection: Reflectometry analysis is used to detect and localize moisture ingress or leakage within an insulation layer.
• Impedance measurement / TDR: Time Domain Reflectometry (TDR) measures impedance discontinuities along the sensing line to locate faults and estimate their position.
• Embedded sensing wire: A 1.5 mm² bare tinned-copper wire or 1.5 mm² copper wire is integrated into the insulation. A spacer presses the copper wire against or into the insulation layer to provide consistent electrical coupling.
• Drainage: PPS (polyphenylene sulfide) drain plugs can provide controlled drainage paths while maintaining the required mechanical and environmental resistance.
• Multi-state corrosion sensing: The system can incorporate corrosion-sensor elements representing different surface conditions, for example:
  • bare steel
  • painted/coated steel
  • other protected or unprotected metal states
• Analysis: Changes in impedance, dielectric properties, and reflectometry response can be analyzed to distinguish dry insulation, localized humidity, water ingress, insulation damage, and corrosion-related changes.

A key point is that TDR primarily localizes impedance discontinuities; humidity localization depends on how moisture changes the electrical properties of the sensing structure. The sensor geometry, wire-to-insulation coupling, dielectric constant, and calibration therefore strongly affect the achievable localization accuracy.