الفهرس 
Ceramic Insulators
FLASHOVER VOLTGE TEST OF POLYESTER COMPOSITE INSULATORSOnly 14 pages are availabe for public view
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Abstract
The polymeric composite insulators have been used as outdoor insulators in electrical transmission lines and sub-stations over last few decades due to their advantages such as light weight, very good mechanical properties, easy for transportation and structure, resistance to vandalism and less maintenance requirement. Ceramic, porcelain and glass insulators have been in the service since the late 1880s, so their service performance is well known. However, the composite insulators performance in service is limited because of little understanding of the service performance and behavior of composite insulators when exposed to combined voltage stresses and environmental conditions over a long period. Due to the increasing transmission voltages, the requirements for high reliability of the power system is essential.
The most important factor in the design and dimensioning of high voltage insulators is flashover voltage as it can lead to costly outages for power utilities and customers. Pollution flashover is affected by many factors such as type of pollution, conductivity of water, surface condition, creep age distance and environmental weather conditions.
The investigations existing on this topic can be mainly classified into two subjects: one is the experimental pollution flashover voltage tests, and the other is the physical and mathematical analysis of pollution flashover voltages. Pollution flashover voltage tests require a significant investment in raw materials. The high cost of materials motivates more research using mathematical analysis of the pollution flashover process. The mathematical models are constructed based on extensive analysis of the flashover voltage mechanism. The flashover voltage can be evaluated using mathematical models, thus providing a theoretical basis for coordinating insulation.
Recently, the metaheuristic optimization algorithms are becoming very essential in engineering applications. The various advantages such as easy to implement, no gradient information required and can overcome local optima make metaheuristic optimization algorithms an avenue for solving a wide range of problems including different disciplines.
Given this brief background, this thesis reports the results of flashover voltage test in different weather conditions such as dry, wet and salty wet. Different algorithms such as (Grey Wolf Optimization, Grey Wolf and Cuckoo Search Hybrid Optimization, Whale Optimization Algorithm and Seagull Optimization Algorithm) are constructed to predict the best concentration of Alumina Tri-Hydrate (ATH) filler in polyester resin to achieve the highest flashover voltage value. Also the compressive strength, thermos-gravimetric analysis (TGA) and derivative thermos-gravimetric (DTG) of polyester resin are tested according to standard techniques and requirements.
The results showed that the flashover voltage performance of polyester is improved with the increase of ATH filler concentration. Optimal percentage of Filler is illustrated from different point of views. Comparison is done between different optimization methods and optimal method with minimum percentage of deviation is obtained.