Modelling Of Leakage Current On Conductive Surface For Outdoor Insulators

Abd Rahim, Noor Afiqah (2021) Modelling Of Leakage Current On Conductive Surface For Outdoor Insulators. Masters thesis, Universiti Teknikal Malaysia Melaka.

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Abstract

The insulation system is the most important part in the high voltage applications to prevent the flow of leakage current to undesired path. Solid outdoor insulators are one of the basic elements in a power system such as in the transmission and distribution system. The outdoor insulator commonly exposed to environmental pollution. The presence of water like raindrops and dew on the contaminant surface can lead to the insulator surface degradation. The contaminant particles may be dissolved into water. Thus, this condition can caused the formation of the conductive path that can lead to the flow of the current due to the surface discharge event. However, the physical process of this phenomenon is not well understood. In order to understand the propagation of the surface discharge on the insulator, the mechanism for the charge carrier generation and transportation must be known. Hence, in this study, the mathematical model of leakage current on the outdoor insulator surface using the Nernst Planck theory that accounts for the charge transport between the electrodes (negative and positive electrode) and charge generation mechanism is developed. Meanwhile, the electric field obeys Poisson’s equation. In this model, one-dimensional (1-D) model is studied. The charge continuity equations and Poisson’s equation solved using a non-dimensional framework to reduce the difficulty while doing the simulation. Then, this model is solved numerically using the method of lines (MOL) technique which converts the partial differential equations (PDEs) into a set of ordinary differential equations (ODEs). The ODEs then solved using an appropriate time integration method ‘ode15s’ in MATLAB. In order to validate the simulation result, experimental work is done according to inclined plane test (IPT) complying with BS EN 60587-2007. Then, the result from both simulation and experimental work is compared for the validation of this model. The findings from the simulation shows that the density of net space charge distribution gives the good correlation to the electric field. Besides, the conduction current also varies depending on the electric field distribution and charge concentration. In addition, The simulation result appears to have good correlation with the experimental result in terms of leakage current rising. Hence, from the simulation, it can, be seen that this mathematical model can be used in order to investigate the leakage current on the outdoor insulator due to the presence of surface discharge. In addition, the permittivity gives the effect to the number of charge produced on the outdoor insulator due to the present of wet contaminant. Thus, the charge will produce more flux in a medium with a lower permittivity than a medium with high permittivity.

Item Type: Thesis (Masters) Electric insulators and insulation, Testing, High voltages, Insulators T Technology > T Technology (General)T Technology > TK Electrical engineering. Electronics Nuclear engineering Library > Tesis > FKE F Haslinda Harun 17 Nov 2021 09:09 17 Nov 2021 09:09 http://eprints.utem.edu.my/id/eprint/25396 View Download Statistic