Investigating the effects of oxidation and thermal degradation on electrical and chemical properties of power transformers insulation

Author

Saha, T.K. ; Darveniza, M. ; Yao, Z.T. ; Hill, D.J.T. ; Yeung, G.

Author_Institution

Dept. of Comput. Sci. & Electr. Eng., Queensland Univ., Brisbane, Qld., Australia

Volume

14

Issue

4

fYear

1999

fDate

10/1/1999 12:00:00 AM

Firstpage

1359

Lastpage

1367

Abstract

This paper describes the analysis of thermally accelerated aged insulation samples to investigate the degradation processes observed in the insulation of aged transformers. Accelerated ageing experiments were performed on paper wrapped insulated conductors in the presence of air and nitrogen environments over a temperature range of 115 to 145°C. Effects of oxidation on the ageing of oil-paper insulation were investigated and results are presented in this paper. The condition of aged insulation samples was investigated by a number of diagnostic techniques: (a) measurements of interfacial polarization spectra by the return voltage method, (b) measurements of molecular weight and its distribution by gel permeation chromatography, (c) surface analysis by X-ray photo-electron spectroscopy, and (d) a study of the oxidation of the oil by UV-visible spectroscopy. Results from these measurements are presented in this paper and are used to analyse the degradation process with special emphasis on oxidation

Keywords

X-ray photoelectron spectra; ageing; chromatography; impregnated insulation; insulation testing; oxidation; paper; polarisation; power transformer insulation; power transformer testing; ultraviolet spectroscopy; visible spectroscopy; 115 to 145 C; UV-visible spectroscopy; X-ray photo-electron spectroscopy; accelerated ageing experiments; air environment; chemical properties; degradation processes; diagnostic techniques; electrical properties; gel permeation chromatography distribution; interfacial polarization spectra measurements; molecular weight measurements; nitrogen environment; oil-paper insulation; oxidation; paper wrapped insulated conductors; power transformers insulation; return voltage method; surface analysis; thermal degradation; thermally accelerated aged insulation; Accelerated aging; Conductors; Nitrogen; Oil insulation; Oxidation; Polarization; Power transformer insulation; Spectroscopy; Temperature distribution; Thermal degradation;

fLanguage

English

Journal_Title

Power Delivery, IEEE Transactions on

Publisher

ieee

ISSN

0885-8977

Type

jour

DOI

10.1109/61.796229

Filename

796229