Materials selection process for electrical insulation application was carried out using Cambridge Engineering Selector (CES) program. Melt mixing technique was applied to prepare polyvinyl-chloride- (PVC-) nanofumed silica and nanomontmorillonite clay composites. Surface analysis and particles dispersibility were examined using scanning electron microscope. Dielectrical properties were assessed using Hipot tester. An experimental work for dielectric loss of the nanocomposite materials has been investigated in a frequency range of 10 Hz–50 kHz. The initial results using CES program showed that microparticles of silica and clay can improve electrical insulation properties and modulus of elasticity of PVC. Nano-montmorillonite clay composites were synthesized and characterized. Experimental analyses displayed that trapping properties of matrix are highly modified by the presence of nanofillers. The nanofumed silica and nanoclay particles were dispersed homogenously in PVC up to 10% wt/wt. Dielectric loss tangent constant of PVC-nanoclay composites was decreased successfully from 0.57 to 0.5 at 100 Hz using fillers loading from 1% to 10% wt/wt, respectively. Nano-fumed silica showed a significant influence on the electrical resistivity of PVC by enhancing it up to 1 × 1011 Ohm·m.

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Voltage collapse is an undesired phenomenon that occurs due to voltage instability and is generally associated with weak or stressed system (heavily loaded lines), long lines, radial networks, faults and/or reactive power shortages. Its occurrence is not frequent in developed countries despite their large and complex networks but its frequency is high in Egypt. Voltage collapses are highly catastrophic anytime they occur. On the Egyptian Interconnected Electrical Grid EIEG, the system collapse phenomenon is frequently experienced and often leads to either partial or total system collapse blackout, which greatly impairs the nation's socioeconomic development and industrialization. This high rate is due to the fact that the EIEG is weak, highly stressed, long and radial in nature hence lacking flexibility. The analysis is performed for EIEG power system. Modern advances in technology are changing the way utility industry increase the transmission of power throughout the country. Distributed energy resources are constantly improving their reliability and power capabilities. The model analysis technique is performed for system using the constant load model. The simulation results are Q-V curves on weak voltages by Power World Simulator PWS Software and Matlab Program.

This paper proposal new structure for improving the optical, electrical characteristics and efficiency of 3rd generation heterojunction quantum dot solar cell (HJQDSC) (ITO/CdS/QDPbS/Au) model by using the quantum dot window layer instead of bulk structure layers cell. Also, this paper presents theoretically analysis for the performance of the proposal HJQDSC (ITO/QDCdS/QDPbS/Au) structure. The new design structure was applied on traditional (SnO2/CdS/CdTe/Cu) and (ZnO/CdS/CIGS/Mo) thin film solar cells which based on sub-micro absorber layer thickness models by replacing the bulk CdTe, CIGS absorber layers and CdS window layer with quantum dot size materials to achieve higher efficiency with lesser usage layer material. Also, it has been studied the effect of using semiconductors layers in quantum dots size on electric and optical properties of thin film solar cells and the effect of window and absorber layers quantum dots radii on the performance of solar cells. Finally, a thermal efficiency analysis has been investigated for explaining the importance of new structure HJQD solar cells.

<span>This paper processed and characterized cost-fewer polypropylene (PP) nanocomposite films; an experimental work has been investigated for studying the electric properties of the new nanocomposite materials and compared with unfilled industrial materials in a frequency range up to 1 kHz. A small addition of nanoparticles (clay, and fumed silica) to polypropylene showed appreciable improvement in the electric reactance and conductance at different frequency up to 1kHz, in addition, an  electric spectroscopy has been measured the electric properties of polypropylene with and without nanoparticles under variant temperatures (20°C, and 60°C). Cambridge Engineering Selector (CES) program were carried out the electrical/mechanical predictable models for the suggested materials. Finally, this paper leads to synthesize electrical insulating polypropylene nanocomposite films where the electrical properties are properly maintained in order to achieve more cost-effective, energy-effective and hence environmentally better materials for the electrical insulation technology.</span>

<span>Polymer nanocomposites possess promising high performances as engineering materials, if they are prepared and fabricated properly. In this research, it has been processed samples of nanocomposite polymers as electrical insulating materials for application on the electric power cables by using the latest techniques of nanotechnology. This paper has been investigated enhanced dielectric and electrical properties of Polyvinyl chloride PVC as matrix have shown that trapping properties are highly modified by the presence of costless nanofillers clay and fumed silica. An experimental work for dielectric loss and capacitance of the new nanocomposite materials have been investigated and compared with unfilled industrial materials. It is found that a good correlation exists in respect of capacitance and dielectric loss values measured with percentage of nanofillers. Thus, it has been investigated the influence of costless nanofillers material and its concentration on dielectric properties of industrial polymers-based composite systems. A comparative study is performed between the unfilled base polymers, the systems containing one type of nanoparticles clay<em><span> </span></em>or fumed silica inside the host polymer with various concentrations.</span>

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