Comparative performance of 11kV silicone rubber insulators using artificial pollution tests

Outdoor insulation is continuously exposed to the elements and its performance is severely affected by the weather conditions. New anti-dry band designs using textured surfaces to achieve better performance under polluted conditions have been proposed. This paper presents a comparative study of silicone rubber polymeric insulators for 11kV systems using artificial pollution tests in accordance with the clean dry layer test fog method specified in IEC60507. A non-textured polymeric insulator design has been selected and compared with an insulator having a textured surface. Both voltage and leakage current signals were measured and digitized through a high-resolution data acquisition system. The signals were then processed to calculate other significant parameters of the test results. These parameters permit direct comparison between different insulator designs under AC and positive DC voltages. Continuous monitoring of the shed surfaces and insulator trunks using an IR camera was undertaken to evaluate the temperature distribution along the insulator profile to identify the formation and location of dry regions on the insulator surface.