الفهرس 
CHAPTER 1: INTRODUCTIONOnly 14 pages are availabe for public view
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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.