Dynamic modelling of pollution flashover on high voltage outdoor insulators
The high voltage outdoor insulators are one of the most important components in the electrical power transmission system. During its lifetime, insulators are exposed to several failures. For this reason, it is crucial to continuously monitor its condition and investigate insulator performance...
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| Format: | Thesis |
| Language: | English English English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/4007/1/24p%20ALI%20AHMED%20ALI%20SALEM.pdf http://eprints.uthm.edu.my/4007/2/ALI%20AHMED%20ALI%20SALEM%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/4007/3/ALI%20AHMED%20ALI%20SALEM%20WATERMARK.pdf |
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| Summary: | The high voltage outdoor insulators are one of the most important components in the
electrical power transmission system. During its lifetime, insulators are exposed to several
failures. For this reason, it is crucial to continuously monitor its condition and investigate
insulator performance under varying degrees of contamination. In this work, new
techniques have been used to diagnose insulators' conditions based on Fast Fourier
Transformer (FFT) Analysis of the leakage current. FFT analysis is commonly employed
to investigate insulator statements under varying degrees of contamination and wetting
rate using harmonic components and phase-shift angle of leakage current. It can be noted
that proposed techniques have shown high efficiency in evaluating insulator status. The
increase in pollution levels on insulators surfaces has affected the performance of
insulators which leads to the occurrence of flashover on the insulator surface. The
investigations carried out to understand the performance of polluted insulators may be
grouped into three categories: natural testing, artificial testing or laboratory testing, and
mathematical models. However, the method of actual testing of insulators suffers from
limitations, for example, it is uneconomical, highly time-consuming, and gives non�reproducible results. So, artificial testing (experiments) and mathematical models have
been used to understand and predict pollution flashover voltages of polluted insulators. In
this study, a new mathematical model, based on the dimensional analysis method (DAM),
is proposed. This model is used to forecast the contamination flashover voltage gradient
of insulators under varying contamination and wetting conditions when subjected to AC
voltages. The arc constants have been extracted from the V-I characteristics curve to
estimate the dimensional constant. The Artificial Neural Network (ANN) and Adaptive
Network-Based Fuzzy Inference System (ANFIS) were utilised also for the prediction of
the mathematical model. Also, in this study, an improved static and dynamic mathematical
model of critical parameters of polluted insulators is proposed based on an extended
equivalent electric-circuit model of a polluted insulator. The effect of arc length and
resistance of the pollution layer on critical flashover voltage investigated using the (RLC) circuit model. Finally, the experimental test results validate the competency of the
proposed dynamic model via accurate performance prediction of polluted insulators. There
is a good agreement between the results of the experiments of polluted insulators obtained
in the laboratory and values calculated from the developed model |
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