الفهرس 
1. INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Electrical treeing is long term degradation phenomenon in polymer material when exposed continuously to high electric field stress. When the electrical tree branches reach the opposite electrode, failure of insulation occurs. So, this electrical treeing represents a significant risk on high voltage insulation. Recently, nanotechnology is used for increasing electrical treeing resistance of insulation. In this thesis, the effect of nanofiller concentration and nanofiller type which is added to silicone rubber nanocomposites on electrical treeing resistance is studied. Accordingly, the preparation of silicone rubber nanocomposite samples considering different nanofiller types is carried out. These nanofillers are silicone dioxide (SiO2), zirconium dioxide (ZrO2), and titanium dioxide (TiO2). Also, silicone rubber nanocomposites with different filler loadings of each nanofiller type are prepared. Scanning Electron Microscope (SEM) images are introduced to examine the dispersion of nanofiller in silicone rubber nanocomposites. Electrical treeing test is carried out considering all prepared samples at constant AC voltage using needle- plane electrode configuration. The evaluation of electrical treeing is carried out based on the tree growth as well as its shape.
In the present thesis, evaluation of breakdown strength of silicone rubber nanocomposites as well as nanofilled transformer oil is also carried out. Transformer oil nanofluid samples are prepared with the same nanofillers types used with silicone rubber nanocomposites samples. Breakdown strength of the silicone rubber nanocomposites as well as nanofilled transformer oil is experimentally measured according to ASTM D1816 standard. This is in order to compare between performance of nanofillers in solid insulation as well as liquid insulation.