Diagnostic and tests

On-site measurements

• Sheath test: Electrical test to determine the condition of the cable's outer sheath
• MV and HV voltage test: Application of an AC voltage between phase and earth
• Tangent-delta measurement: Measurement of the dielectric losses of the cable insulation to assess its overall ageing
• Partial discharge analysis: Detection of a possible weak point on the link (e.g. end-of-life accessory)
• Fault location: Determining the location of a fault on a link
• Methods available: echometry, ground microphone, wire bridge, thermal camera
• Route detection: Determining the route of a cable

Laboratory tests

• Maximum temperature reached during operation
• Presence of residual gas in cross-linked insulation
• Arborescence (water in insulation)
• Moisture content of cable components (Karl Fischer method)
• Recrystallisation status of lead sheaths and quality of paper insulations

Possible intervention departure 24/7