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UV-IR complimentary technologies. TOC. “A picture is worth thousand words”. Live End Corona. Dead End Corona. No corona on IR picture . Corona spots using UV technology. “A picture is worth thousand words”. No corona on IR picture . Corona spots using UV technology.
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“A picture is worth thousand words” Live End Corona Dead End Corona No corona on IR picture Corona spots using UV technology
“A picture is worth thousand words” No corona on IR picture Corona spots using UV technology
UV & IR - Spectral Ranges 12 140 UV Visible Near IR C B A 120 10 100 8 Solar Radiation (µW/cm2/nm ) 80 Filter Transmission (%) 6 60 4 40 2 20 200 300 400 500 600 700 800 900 1000 Wavelength (nm)
UV & IR - Complimentary Applications IR cameras are current related indicators anddetect heat generated often by loose connections. Corona surveys detect voltage related effects resulting from partial insulation failures (typically voltage >6Kv) Partial discharge technology detect the condition of the insulation! Infrared technology detects the condition of the conductor !
Statements “In most cases the IR inspection is able to identify the failure only in a higher stage of failure development”.( INMR 2009 , EGU –HV Laboratory) “IR camera is not suitable for corona discharge inspection, because the rise of temperature can occur only at extremely high corona or in case of some current load.” (monitoring of HV and UHV overhead lines components with UV and IR cameras” , NMR 2009, EGU – HV Laboratory).
Broken strands – three bundled conductor • Notes: • Corona discharge activity is influenced by the distance of the broken strand to the conductor • No noticeable heating for possible IR inspection
No noticeable heating for possible IR inspection Corona discharge activity Bird Caging – Three Bundled Conductor
Spacer damper - clamp failure and broken strands No noticeable heating for possible IR inspection.
Arcing ring horn with ball direction towards the tower leg · The corona discharges occur due to the horn with ball direction towards tower leg. Possible improvement measures are larger ball diameter and/or direction along conductor or outwards tower leg. · No noticeable heating for possible IR inspection.
Conclusions UV inspection of conductors and overhead line fittings is a very reliable way for the detection of corona sources with the possibility to identify the large majority of such sources. The corona discharges on conductors and fittings are most reliably detected under dry conditions. “Monitoring of HV and UHV overhead lines components with UV and IR cameras”. INMR 2009, EGU – HV Laboratory.