Conference Publications

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https://hdl.handle.net/20.500.14170/204

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Browsing Conference Publications by Author "Abd-Rahman R."
  • Publication
    Flashover voltage prediction on polluted cup-pin the insulators under polluted conditions
    ( 2021-01-01)
    Salem A.A.
    ;
    Abd-Rahman R.
    ;
    Kamarudin M.S.
    ;
    Othman N.A.
    ;
    Jamail N.A.M.
    ;
    Nuriziani Hussin
    ;
    Haziah Abdul Hamid
    ;
    Rawi I.M.
    The natural pollution which is mainly affected by the weather conditions are the main cause of flashovers on high voltage insulators leading to outages in power systems. In this work, characteristics of flashover for contaminated cup-pin insulators have been studied based on experiential test and a mathematical model. Information from laboratory test combined with new mathematical model results are used to define Artificial Neural Network (ANN) algorithm and Adaptive Neuro-fuzzy Inference System (ANFIS) for calculated the flashover characteristics (current IF and voltage UF). several of experiments and measurement are carried out for 1:1, 5:1, 10:1 and 15:1 ratios of bottom to top surface salt deposit density on contaminated samples (z). Dimensional Analysis Method (DAM) was used to derive new model for the variables which often effective in the flashover phenomenon of polluted insulators. The model was derived by establishment the relationship between flashover voltage UF and current IF, length of pollution layer LP, exposure time t, arc constant A and layer pollution conductivity of insulator σ. The both arc constants A and n is computed using genetic algorithm. Comparative investigates have clearly shown that the approach AI-based method gives the agreeable results compared to the mathematical model.
  • Publication
    Investigation of Spherical Electrode Grounding System under High Impulse Conditions with Different Polarities
    ( 2021-06-11)
    Haziah Abdul Hamid
    ;
    Mohd Rafi Adzman
    ;
    Noor Hasnizam Hanafi
    ;
    Nor N.M.
    ;
    Abdullah S.
    ;
    Reffin M.S.
    ;
    Etobi N.A.
    ;
    Abd-Rahman R.
    There have been many studies in the pasts, which showed that under high impulse conditions, soil ionization process around the electrode would occur, which results in lower resistance and lower transient voltage on the electrode. Several factors have also been found to affect the ionization process in soil such as; soil types and its grain sizes, moisture contents in the soil, earth electrode configurations, impulse polarity, the location of the injection point, the shape of response time, etc. In this paper, spherical electrodes grounding is used to study the ionization process in the grounding system under different impulse polarity of the current. The experiment was done by field measurement using a commercially available impulse current generator. It was found that lower earth resistance was seen to decrease with increasing current magnitudes for both impulse polarities. In addition, it was found that at low impulse current with negative polarity has a higher resistance than that of positive polarity. This paper is, therefore, to investigate towards improvement on grounding electrode's design, which would consider soil ionization process