Understanding the influence of ambience on thermal ageing of natural ester liquid. Issue 2 (1st March 2019)

• Record Type: Journal Article
• Authors: Thakur, Soumya; Panigrahi, Suraj Kumar; Mishra, A.K.; Sarathi, Ramanujam
• Is Part Of: IET science, measurement & technology. Volume 13:Issue 2(2019)
• Page Start: 123
• Page End: 130
• Publication Date: 2019-03-01
• Subjects: partial discharges -- corona -- visible spectra -- ageing -- harmonic distortion -- ultraviolet spectra -- Fourier transform infrared spectra -- fluorescence -- organic insulating materials; natural ester liquid -- corona inception voltage -- CIV -- negative DC voltage -- harmonic voltage -- voltage waveform -- thermally aged liquid -- corona activity -- AC voltages -- nitrogen ambience -- harmonic distortions -- ultrahigh‐frequency signal -- phase‐resolved partial discharge analysis -- UHF signal -- corona discharges -- Fourier transform infrared spectroscopy -- carbonaceous particles -- chromophoric moiety -- red shift -- absorption band -- ultraviolet‐visible spectra -- fluorescence spectroscopy -- condition monitoring -- frequency 1.0 GHz; Measurement -- Periodicals; Electrical engineering -- Periodicals; Electronics -- Periodicals; Nanotechnology -- Periodicals; Electromagnetism -- Periodicals; Medical instruments and apparatus -- Periodicals; 621.3
• DOI: 10.1049/iet-smt.2018.5079
• Languages: English
• ISSNs: 1751-8822

Abstract

Abstract : Ambience during thermal ageing of ester liquid has a high impact on corona inception voltage (CIV) under AC and DC voltages. The CIV is high with ester liquid thermally aged in nitrogen ambience and is the least with air aged. CIV is high under negative DC voltage followed by positive DC and AC voltages. CIV reduces with increase in harmonic voltage and the reduction is predominant with harmonic voltages with higher total harmonic distortions. Corona activity radiates ultra‐high‐frequency (UHF) signal with its dominant frequency at 1 GHz. Phase‐resolved partial discharge analysis carried out using UHF signal indicates that corona discharges occur at the peak of the voltage waveform. The magnitude of discharges is less in thermally aged liquid but the number of discharges increases. Fourier transform infrared spectroscopy analysis indicates the formation of carbonaceous particles with thermal ageing. Thermal ageing of ester liquid causes to form new chromophoric moieties causing red shift of absorption band in ultraviolet–visible spectra. Fluorescence spectroscopy traces the characteristic variations due to thermal ageing, which can be adopted for condition monitoring.