Original scientific paper

Oil-impregnated paper bushing insulation diagnostics

Diego Robalino ; Megger
Ismail Güner ; Hydro­Québe
Peter Werelius ; Megger

Abstract

As reported in CIGRE TB 642, windings, tap changers and bushing related failures are the major contributors to transformer failure. About 17 % of transformer breakdowns are caused by bushing failure which is often followed by explosion, tank rupture, fre and potential human harm. To date, the insulation system in high voltage and extra-high voltage bushings is mainly oil-impregnated paper and resinimpregnated paper; in fewer cases, resin-bonded paper. Some of the advantages of using oil-impregnated paper bushings, listed in CIGRE TB 445, are the ability to be used at any voltage design level with minimum partial discharge activity, relative low cost, the possibility to perform nonintrusive dielectric diagnosis using dielectric response methods, as well as the extraction of oil samples for dissolved gas analysis. Evidencing these advantages, a combined analysis of the insulation condition of EHV bushings using dielectric frequency response measurements and dissolved gas analysis are carried out at a major North American utility and are described herein.

Keywords

high voltage bushing; oil-impregnated paper insulation; dielectric frequency response; DGA

Hrčak ID:

195048

URI

https://hrcak.srce.hr/195048

Publication date:

23.11.2017.

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