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

摘要

This paper describes the analysis of thermally accelerated agedninsulation samples to investigate the degradation processes observed innthe insulation of aged transformers. Accelerated ageing experiments werenperformed on paper wrapped insulated conductors in the presence of airnand nitrogen environments over a temperature range of 115 to 145°C.nEffects of oxidation on the ageing of oil-paper insulation wereninvestigated and results are presented in this paper. The condition ofnaged insulation samples was investigated by a number of diagnosticntechniques: (a) measurements of interfacial polarization spectra by thenreturn voltage method, (b) measurements of molecular weight and itsndistribution by gel permeation chromatography, (c) surface analysis bynX-ray photo-electron spectroscopy, and (d) a study of the oxidation ofnthe oil by UV-visible spectroscopy. Results from these measurements arenpresented in this paper and are used to analyse the degradation processnwith special emphasis on oxidation