الفهرس | Only 14 pages are availabe for public view |
Abstract Recently, nanotechnology appears in a lot of scientific fields. The use of this technology in electrical engineering has found a great interest from researchers. In the present thesis, effect of adding nanoparticles on dielectric properties is studied. Complex permittivity is one of the most important dielectric properties required for evaluating dielectric materials (either ceramic or polymeric). The effect of filler volume fraction, filler dielectric constant and particle shape is studied through a proposed model which take the effect of interaction zone between the nanofiller and the resin material into consideration. The validity of the proposed model for evaluating the complex permittivity of nanocomposites is achieved by comparison with experimental results and a good agreement is found. Flashover is a common reason of insulator failures especially in contaminated areas like industrial and coastal regions. Therefore, nanotechnology is used as an attractive and efficient solution for this problem. A nanosized carbon black is used to control the current-voltage (I-V) characteristics of a proposed coating material to improve proactive flashover performance which is presented by reducing the dry band arcing as well as the surface current over insulator. A theoretical model for computing the dry band arcing voltage is presented and experimentally verified by doing experiments on glass slaps coated with the proposed material at different nanosized carbon black loadings. Surface current is experimentally measured for proposed coating applied on real field insulators. Also, a simple technique to enhance the flashover performance of high voltage insulators is presented. The proposed technique depends on coating only the insulator metal cap and pin. Studying the effect of room temperature vulcanized (RTV) silicone rubber for metal cap and pin coating is presented. Another improvement is done by enhancing the cap and pin coating with a thin layer of the nonlinear nanofilled material. A theoretical model based on developing Obenaus’s model is presented to calculate the flashover voltage. A good agreement between experimental and model results is achieved. For an extra improvement in the performance of high voltage insulators, a proposed superhydrophobic material is presented as a coating. Material preparation technique is presented. Also, application of the proposed superhydrophobic material as a coating on a ceramic slap is studied. Finally, uncoated and superhydrophobic coated ceramic slaps are subjected to high voltages and the leakage currents for both are measured. The obtained results provide an evidence for an excellent performance of the superhydrophobic coated insulator. |