Chromatic monitoring of transformer oil condition using CCD camera technology



Elzagzoug, Ezzaldeen
Chromatic monitoring of transformer oil condition using CCD camera technology. Doctor of Philosophy thesis, University of Liverpool.

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Abstract

Power transformers are essential components within the power distribution system. Transformer failures having a high economic impact on the distribution operators and the industrial and domestic customers. Dielectric mineral oil is used in transformers for electrical insulation between live parts, cooling and protection of the insulation papers in the transformer. Oil contamination and changes in the chemical structure of the oil result in the decay of insulation paper and reduced insulation and cooling which can lead to a transformer failure. The general approach to oil monitoring has been for an operator to examine the colour index (ASTM) of the oil, electrical strength, acidity, water contents and dissolved gas analysis results and form an opinion as to the extent of oil degradation. Chromatic techniques enable data from di↵erent sources to be combined to give an overall evaluation about the condition of a system being monitored. One of the main goals for this work was to use chromatic techniques for integrating the oil data from the di↵erent sources and sensors. In addition the chromatic approach enables liquids to be monitored optically so a second aim was to apply chromatic optical oil monitoring using portable system by transmitting polychro- matic light through the oil sample, which is contained in a transparent cuvette and imaged using a mobile phone camera. A number of oil samples were optically analysed with portable chromatic sys- tem and the optical data was compared with the colour index and chromatically companied with the dissolved gas and other oil data to give overall evaluation of oil degradation. The chromatic optical result compared favourably with the colour index. It was also possible to classify the oil samples chromatically into categories of low, medium and high degradation. This enabled the chromatic data combination approach to be implemented as a prototype system in Matlab software that an operator could use to get a classification of an oil sample. Essential experiment was introduced to monitor di↵erent oil particles by obtaining the result of di↵erent filtered samples through the filter paper. Beside the ability to analyse data and distinguish between fresh and contam- inated oil samples the chromatic technique has the ability to track the history of di↵erent degraded oil samples which can give an indication about failure faults and it could give a prediction of any future faults. Therefore a commercially viable reliable system can be developed to extend the service life and extend the maintenance schedules. These monitoring systems could lead to extending the service life of the transformers, making the electricity supply more reliable and giving the consumer a better quality of life.

Item Type: Thesis (Doctor of Philosophy)
Additional Information: Date: 2013-06-26 (completed)
Subjects: ?? TK ??
Divisions: Faculty of Science and Engineering > School of Electrical Engineering, Electronics and Computer Science
Depositing User: Symplectic Admin
Date Deposited: 14 Aug 2014 08:54
Last Modified: 16 Dec 2022 04:39
DOI: 10.17638/00012233
Supervisors:
  • Spencer, Joseph
URI: https://livrepository.liverpool.ac.uk/id/eprint/12233