Prediction of remaining service life of polymer insulators

Haddad, G 2016, Prediction of remaining service life of polymer insulators, Doctor of Philosophy (PhD), Electrical and Computer Engineering, RMIT University.

Document type: Thesis
Collection: Theses

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Title Prediction of remaining service life of polymer insulators
Author(s) Haddad, G
Year 2016
Abstract With the severe weather pattern in Australia over recent years, the high voltage polymer insulators in our power systems are severely stressed due to constant exposure to rain, pollution, heat and ultraviolet radiation. In spite of many benefits that polymer-based insulators can offer in comparison to their ceramic counterparts, they can fail mechanically and electrically.

The common failure modes of polymer insulators include brittle fracture, flashover, and mechanical failure. Polymers will deteriorate over time due to exposure to environmental factors. Various complex mechanisms may result in polymer chain scission leading to changes in properties. There have been numerous studies of individual factors; however, the combined effect of these factors has not been described.

In addition, in Australia, the severe weather patterns and increasing demand on electricity over recent years have exerted additional stress on the polymer insulators that are in current usage. Therefore, premature failures can be expected. Any failure in the large population of polymer insulators is a major concern for power utilities in Australia. When the insulators fail, the power supply to customers is disrupted and failures may initiate sparks and arcing that could lead to catastrophic events such as pole fires and bushfires. In 2007, sparks and flashovers on power lines due to insulator failure caused bushfires in Western Australia and resulted in loss of property and human life and this scenario was repeated on the 7th of February, 2009, in Victoria, Australia.

Currently, visual inspection is performed by line inspectors on foot, on a bucket truck or on board a flyby helicopter, the latter being, currently, the most commonly used method; sometimes a daytime corona camera or infrared thermal camera is used. These current techniques do not provide any indication of the remaining service life of the insulators.

This thesis investigates the long-term influence of ultraviolet radiation, moisture and heat on the chemical composition of polymer insulators. The research concentrates on one type of polymer insulators, specifically silicone rubber insulators. Comprehensive laboratory testing is performed and results are analysed. Both a statistical and non-statistical approach is applied to predict the remaining service life of the insulators.

The main objective of this thesis is to develop a novel remaining service life prediction tool for polymer insulators, which is expected to have a significant impact in the following ways:

a better understanding of the long-term performance of polymer insulators under unique weather conditions in Australia and overseas

a better maintenance and replacement strategy for polymer insulators on high voltage transmission and distribution lines
Degree Doctor of Philosophy (PhD)
Institution RMIT University
School, Department or Centre Electrical and Computer Engineering
Subjects Agro-ecosystem Function and Prediction
Chemical Characterisation of Materials
Statistical Theory
Keyword(s) Prediction
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Created: Wed, 19 Oct 2016, 10:20:14 EST by Keely Chapman
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