الفهرس 
Artificial Neural Network ResultOnly 14 pages are availabe for public view
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Abstract
Nanotechnology is an emerging technology in the scientific world. It’s one of the fastest growing fields in research and technology. Insulating materials play a vital role in the design and performance of electrical power systems at steady-state and transient state conditions. The last decade has witnessed significant developments in the area of nano dielectric materials. Significant effects of nano scale fillers on electric, thermal and mechanical properties of polymeric materials have been observed.
The electrical, mechanical and thermal properties are more important for the insulating materials used in high voltage applications. The present thesis represents a comprehensive study on polymer nano materials that are used in high voltage insulation. The study goals are to determine the impact of nanofiller size, type and distribution of the particles into the polymer matrix on the electrical, mechanical and properties of polyester nano materials for comparison against pure polymer and traditionally materials used as insulation systems in high voltage engineering.
In this thesis, an experimental investigation was made to explore the use of nanotechnology to enhance the performance of polymer nanocomposites as insulation material. Cylindrically shaped polyester composite samples have been prepared with different weight percentages (1%, 3%, and 5%) of nanofillers silicon dioxide (SiO2) and
Titanium dioxide (TiO2) to improve the electrical and thermal performance of high voltage insulations. The results showed that addition of this type of nano particles contributed in improving the electrical properties and flashover voltage for all samples. The flashover voltage of composites containing nano SiO2 is higher than containing nano TiO2. Flashover voltage reached 41 KV for polyester sample without fillers against 61 KV and 58 KV for polyester sample loaded with 5% nano SiO2 and 5% nano TiO2 in dry conditions respectively.
A comparison between nanofillers in various industrial environmental conditions (cement, phosphate and silica fume) indicated higher flashover voltage values for polyester nanocomposite containing nano SiO2 fillers than that containing nano TiO2 filler at all filler concentrations. Experimental results showed that nano titanium dioxide (TiO2) and nano silicon dioxide (SiO2) materials improved the electrical, mechanical and thermal properties of polyester compared with pure polymeric materials. It’s concluded that, polyester loaded with 5% nano SiO2 can be used for heavy electrical applications in dry and various coastal environmental pollutions.
Mechanical properties were also studied and described. The composite materials with polyester properties were mechanically evaluated by conducting mechanical tests which include compressive and tensile strength. The tests showed the best enhancement of the mechanical properties up to 3% vol. of SiO2 followed by a decreases of the strength. Moreover, the thermal stability and decomposition rate of
polyester nanocomposite was studied by using thermogravimetric analysis (TGA) technique.
An Artificial Neural Network ”ANN” applied to estimate the flashover voltage under different weather conditions by using measured values of flashover and voltage of pure polyester of titanium dioxide (TiO2) and silicon dioxide (SiO2) as nanofillers with various concentrations. The measured flashover voltage values of each loaded specimen under various weather conditions such as dry, coastal and industrial are used train feed-forward-neural-network (FNN). This network is aimed at predicting the flashover voltage of polymeric insulators at different weather conditions with varying type and percentage concentration of nano filler. The results showed that the FNN can be used to represent data with accuracy of 98%. Then a comparison between the laboratory measurements of flashover voltage of insulator and this predicted by FNN are reported. These results prove that FNN can be considered a successful avenue to evaluate the electrical performance of the investigated polymer nanocomposite insulators under different contaminated-weather conditions.