Modelling the dielectric response measurements of transformer oil

Bandara, Kapila, Ekanayake, Chandima and Saha, Tapan Kumar (2015) Modelling the dielectric response measurements of transformer oil. IEEE Transactions on Dielectrics and Electrical Insulation, 22 2: 1283-1291. doi:10.1109/TDEI.2015.7076832

Author Bandara, Kapila
Ekanayake, Chandima
Saha, Tapan Kumar
Title Modelling the dielectric response measurements of transformer oil
Journal name IEEE Transactions on Dielectrics and Electrical Insulation   Check publisher's open access policy
ISSN 1070-9878
Publication date 2015-04-01
Year available 2015
Sub-type Article (original research)
DOI 10.1109/TDEI.2015.7076832
Open Access Status
Volume 22
Issue 2
Start page 1283
End page 1291
Total pages 9
Place of publication Piscataway, NJ United States
Publisher Institute of Electrical and Electronics Engineers
Collection year 2015
Language eng
Formatted abstract
Dielectric polarization based measurements have been used as one of the useful techniques to characterize the quality of transformer oil. Further, understanding the variation in dielectric response of oil is important to accurately interpret the condition of a transformer composite insulation system. In this paper, the behaviour of insulating oil during frequency domain and time domain dielectric response measurements is investigated. A commercially available natural ester and mineral oil are used for this study. Observed dielectric responses have revealed that existing models which have been in use to describe polarization phenomenon in insulating liquids are insufficient to characterize the exact response of oil obtained from frequency and time domain measurements. This paper proposes two new models for characterizing frequency and time domain response of oil based on the charge transport phenomenon at the electrode interface. The phenomenon in frequency and time domain response of oil has been characterized with an equivalent circuit model and mathematical model respectively, which have been deduced by considering electrode polarization effect and diversity of ionic mobility. The proposed models are tested against measured results and then the applicability verified. Correlation between AC conductivity and low frequency dispersion of real permittivity has also been identified in the presented work. This relationship has been explained with a new mathematical model with nearly S- shaped sigmoid growth. Finally, the impact of parasitic phenomenon called Electro Hydro Dynamic (EHD) motion on dielectric response measurement has been investigated. Two mineral oil samples obtained from operational transformers are used to study the influence of EHD motion.
Keyword Dielectric response modelling
Electrode polarization (EP)
Frequency domain response
Low frequency dispersion (LFD)
Natural ester (NE)
Polarization and depolarization current (PDC)
Universal capacitance
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
School of Information Technology and Electrical Engineering Publications
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