1. Application of Cole–Cole model to transformer oil‐paper insulation considering distributed dielectric relaxation
- Author
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Sivaji Chakravorti, Biswendu Chatterjee, S. K. Ojha, and Prithwiraj Purkait
- Subjects
transformer oil-paper insulation ,dielectric testing techniques ,Materials science ,Transformer oil ,power transformer insulation ,lcsh:QC501-721 ,Energy Engineering and Power Technology ,Dielectric ,dielectric relaxation ,frequency domain ,Dielectric withstand test ,cable insulating oil ,law.invention ,ionic liquids ,oil-paper insulated transformers ,law ,elementary Debye relaxation properties ,lcsh:Electricity ,Cole–Cole diagram ,Time domain ,Electrical and Electronic Engineering ,time domain dielectric response ,Transformer ,transformer oil ,distributed dielectric relaxation ,paper ,dielectric mixtures ,Mechanics ,distribution density functions ,many-body interaction process ,Cole–Cole model ,polar liquids ,Nonlinear Sciences::Exactly Solvable and Integrable Systems ,Frequency domain ,dielectric materials ,insulation condition assessment ,Cole–Cole plots ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,lcsh:TK1-9971 ,Cole–Cole equation ,Test data - Abstract
Researchers have been exploring dielectric testing techniques both in time and frequency domain for insulation condition assessment of oil-paper insulated transformers. In a practical dielectric system, dipoles are found to behave according to a distribution of elementary Debye relaxation properties. Suitable distribution density functions have been proposed to characterise such many-body interaction processes. Cole–Cole diagrams can be one of the methods for studying the nature of frequency dependency of dielectric materials of complex structure. Cole–Cole plots are commonly used for characterising different materials such as dielectric mixtures, ionic liquids, cable insulating oil, polar liquids etc. The scope of its application for assessing transformer oil-paper insulation considering distributed relaxation process has not been explored yet. The present contribution discusses mathematical formulations used for transforming the experimentally obtained time domain dielectric response test data to distribution domain and further to frequency domain for obtaining the Cole–Cole plots. Findings about the influence of various operating conditions and insulation status on the Cole–Cole diagram have been reported in this contribution. Results of tests on field transformers are also presented. This paper attempts to employ the features of Cole–Cole diagrams as potential indicators for analysing condition of the oil-paper insulation considering distributed relaxation process.
- Published
- 2019
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