UV-IR complimentary technologies

TOCTOC

Can the corona camera replace the IR technology?

What is the difference between IR and corona inspections ?

How can I use the UV & IR technologies to have complete overview?

““A picture is worth thousand words”A picture is worth thousand words”

No corona on IR picture

Live End Corona

Dead End Corona

Corona spots using UV technology

No corona on IR picture Corona spots using UV technology

““A picture is worth thousand words”A picture is worth thousand words”

Wavelength (nm)

Filte

r Tra

nsm

issi

on(%

) UV Visible

200 300 400 500 600 700 800 900 1000

20

40

60

80

100

120

140

2

4

6

8

10

12

Sola

r Rad

iatio

n (µ

W/c

m2 /n

m )

C B A Near IR

UV & IR - Spectral RangesUV & IR - Spectral Ranges

IR cameras are current related indicators and detect heat generated often by loose connections.

Corona surveys detect voltage related effects resulting from partial insulation failures (typically voltage >6Kv)

UV IR

Infrared technology detects thecondition of the conductor !

Partial discharge technology detect the condition of the insulation!

UV & IR - Complimentary ApplicationsUV & IR - Complimentary Applications

StatementsStatements

“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).

UV & IR - SummaryUV & IR - Summary

UVThermo vision

Detection of UV emission from corona and arcingSensitive to heat, detection of hot spots

Voltage dependentCurrent dependent

Does not require loading of linesIncreased load of lines is often required

Not affected by solar radiationAffected by intense sunshine

Defects often detected at earlier stage of degradation

Defects often detected at more advanced stage of degradation

Notes:1. Corona discharge activity is influenced by the distance of the broken strand to the conductor2. No noticeable heating for possible IR inspection

Broken strands – three bundled conductorBroken strands – three bundled conductor

Bird Caging – Three Bundled ConductorBird Caging – Three Bundled Conductor

Corona discharge activity

No noticeable heating for possible IR inspection

No noticeable heating for possible IR inspection.

Spacer damper - clamp failure and broken strandsSpacer damper - clamp failure and broken strands

· 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.

Arcing ring hornArcing ring horn with ball direction towards the tower legwith ball direction towards the tower leg

Conclusions 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.

IR UVTwo are Two are better better than than one one