A dissertation submitted to the Faculty of Engineering and the Built
Environment, University of the Witwatersrand, in fulfilment of the requirements
for the degree of Master of Science in Engineering
Date submitted: 28 August 2015 / Many generator transformers were installed many years ago during the initial
commissioning of Eskom’s power stations. Many of these transformers have started
showing signs of significant ageing of the paper insulation and hence require regular
monitoring. There are two methods that are currently being employed to assess the
degree of ageing of the paper insulation in a generator transformer, which are paper
sampling and furan level measurement.
This dissertation investigates an alternative method of predicting the degree of ageing of
the paper insulation instead of what is used currently. This method uses the Arrhenius
equation that relates time and temperature to determine the degree of degradation of
organic materials. The reliability of the Arrhenius estimation method is assessed by
comparing the predicted DP (Degree of polymerisation) values with the measured DP
values of the same transformer paper insulation.
The results obtained showed that there is reasonable correlation between the DP values
estimated from the Arrhenius equation and the DP values estimated from the measured
furan levels.
The accuracy of the prediction method is reduced when the oil temperature
greatly differs from the paper insulation temperature.
The application of the Arrhenius equation to estimate the ageing of paper insulation is a
great milestone in the quest to predict the remaining life of a transformer. It is the only
method available to do this prediction and using online temperature measurement on
transformers makes the method more reliable. / MT 2017
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/23513 |
| Date | January 2015 |
| Creators | Metebe, Michael Tebogo |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | Online resource (iv, 85 leaves), application/pdf, application/pdf |
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