A Basis Study on Outdoor Insulators of Organic Materials

This paper describes the results of a basic study on the tracking resistance, weathering properties and water absorption of high voltage polymer insulators which are the most important factors for outdoor use. The artificial tracking test proposed in this paper requires a shorter time than the conventional test methods and is capable of ranking materials even when such ranking cannot be made by the conventional test methods. A good correlation was found between the results of this tracking test and those of our outdoor exposure test. The increase in surface leakage current on insulators during the outdoor exposure test appeared related to the decrease in hydrophobicity of the insulator surface, and the shapes and mounting of the insulators greatly influenced their performance. Polymer insulators are highly stressed on the energized end, which should be noted particularly from the viewpoint of water absorption of the shed.