Effect of ESDD/NSDD on AC Flashover Characteristics of Conventional and Textured SiR Outdoor Insulators

Pollution flashover occurs when soluble and non-soluble pollutants cover the surface of an insulator, and this may eventually reduce its performance. In this investigation, the most common pollutant types sodium chloride (NaCI), was used as a soluble material (ESDD) and kaolin as a non-soluble material (NSDD). A conventional (CONV) design of silicone rubber (SiR) insulator was selected for this study and compared with an insulator having a 6 mm textured surface (TT6). The insulators were preconditioned and contaminated in accordance with a modified version of IEC 60507. The AC voltage ramp test was utilized to produce a flashover voltage <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathbf{V}_{\mathbf{FOV}})$</tex> at different pollution levels. The purpose of this study was to investigate the impact of soluble (ESDD) and non-soluble (NSDD) materials on the flashover characteristics of both insulator designs. The <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{V}_{\mathbf{FOV}}$</tex> dependency on the pollution severity level was quantified. The influence of SiR profiles on the mean <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{V}_{\mathbf{FOV}}$</tex> was also examined. The test results show that the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{V}_{\mathbf{FOV}}$</tex> of the silicone rubber insulator substantially decreased with the increase in both ESDD and NSDD values. For different ranges of pollution severity levels, it was found that the textured (TT6) insulator can offer an increased <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{V}_{\mathbf{FOV}}$</tex> performance up to 11 % compared with the average <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{V}_{\mathbf{FOV}}$</tex> of the conventional insulator.