A Technique fortheOptical Detection and Analysis ofDry Band Arcs on aComposite Insulator

Videocameras havebeenusedinHighVoltage (HV) testing formanyyears, astheyprovide aconvenient meansof optically recording theevents ofatest. Forexample, highspeed video cameras cancapture pre-breakdown phenomena, andUV sensitive cameras canenable visualisation ofcoronadischarge. However, theuseofmachine vision cameras inconjunction with realtimeimageprocessing, creates notjusta visual aid,but transforms thecameraintoa measurement instrument. This paperdescribes theimplementation ofaunique system into asalt fogchambertesting facility; asusedforageing andperformance tests on HV insulators. The systemprovides threedistinct benefits indry-band arcobservation. A synchronised leakage current trace anddischarge imageallow adirect comparison of thetwo,onaunified timescale. Tomakelocating discharges on theinsulator profile mucheasier, drybandarcimagesare superimposed ontoa pre-captured imageofthetestobject. Finally, theimageisprocessed andbrokendownintoregions of interest, enabling aspatial histogram ofdischarge occurrences to beproduced.