Comparative Inclined Plane Tests On Silicone, Porcelain, And RTV Coating–Porcelain Insulators Under Various DC Voltages

Outdoor insulators are subjected to several environmental stresses due to the combination of pollution, humidity, and high voltages (AC or DC). The insulation housing materials should have acceptable erosion resistance. The inclined plane tracking (IPT) and erosion tests are considered reliable lab tests for the evaluation of erosion resistance of solid outdoor insulators. The IPT experimental setup, procedure, and acceptance criterion under AC voltage are outlined in two international standards, namely ASTM D2303 and IEC 60587. There is no IPT standard for evaluating insulation materials under DC voltages. This paper aims to evaluate quantitively the erosion resistance of the surface of different insulating materials under DC voltage stresses. Three types of insulators are investigated in this paper; Room temperature vulcanized silicone insulator rubber (RTV-SIR) with 45% Aluminium Tri-Hydrate (ATH), Porcelain samples were provided from commercial manufacturers which are identical to what is being erected in the field, RTV Coating-Porcelain insulators. The porcelain insulators show superior performance over the other insulators. The silicon rubber insulators are subjected to deep erosion. The RTV coating porcelain insulators lose a portion of the coating, forming pods that help in the collection of pollution. Also, the results show that +DC voltages are more severe than -DC voltages as it causes more erosion for the different insulators.