There are different types of pollution, including sand pollution or earth dust, industrial pollution with large amounts of solid sediments, chemical pollution and smoke. Flashover process in insulators is done in separate steps.
The applied voltage wave, which is called AC and DC voltages, has a significant effect on the intensity of this process. In the case of AC voltages, arc propagation on the insulating surface takes several cycles. Surface properties also play an important role in the flashover process of insulation pollution. The insulating surface can be classified as hydrophilic or hydrophobic.
While hydrophilic surfaces are usually associated with glass and ceramic insulators, hydrophobic surfaces are characterized by polymer insulators or porcelain insulators with a polymer coating, such as RTV or RTV modified with nanoparticles to increase the insulating properties. The aim of this study is to compare porcelain insulators with coatings. Nano RTV with uncoated and RTV coated insulators were electrically stable at different levels of contamination.
The artificial pollution test was performed in the clean fog test on coated and uncoated insulation. In addition, a comparison between the surface hydrophobicity of these insulators was made by evaluating the contact angles.
Finally, in order to evaluate the effect of pollution severity through electrical stability of insulators on reliability, the life expectancy model was improved and modified. This modified model was used to evaluate the reliability and performance of RTV-coated, nano-RTV-coated, and uncoated porcelain insulators.
The results show that the use of nano-RTV coated insulators can improve the lifetime and failure density performance of insulators compared to traditional and uncoated coatings, especially in polluted areas.
Among the main features of insulators with RTV coating, we can mention such things as high electrical endurance, high mechanical endurance, endurance against temperature changes, and finally, it affects the life span and possibility of failure of the coated equipment.
It is impressive. In a study, Dr. Taqvai and colleagues investigated this issue. In this study, ceramic insulators manufactured by Iran’s Insulator Company have been used, and the modeling results have shown a significant increase in lifespan and a reduction in the probability of failure of coated insulators compared to uncoated insulators. The obtained results show that the coated sample in environments with high pollution performs well in terms of electrical discharge compared to the insulator withoutThe cover shows. According to the analysis carried out in this research work, the life expectancy and expected failure probability for the covered insulator in the presence of pollution with the ESDD pollution criterion has been significantly improved.
The results of the electrical discharge curves based on the amount of contamination related to the uncoated and coated insulators in this research are given below and a significant decrease in the electrical discharge threshold voltage values can be observed with the increase in the amount of contamination. The reason for this is the creation of higher conductivity of the insulator surface in environments with high pollution and as a result of the phenomenon of electric discharge at lower voltage levels. The electric discharge voltage related to the coated sample is increased at each pollution level compared to the uncoated insulator, which indicates the improved performance of the coated insulator and is due to the high hydrophobicity and insulation properties of these coatings.
