Study of inverted T-shape insulator strings in icing conditions

Abstract

For power transmission lines operation in icing conditions flashover problem of insulator strings is a serious and intractable problem. Once it happens, can lead to power line face tripping and longtime power outage. This paper focus on lab based experimental study of analyzing inverted T-shape insulator strings configuration in icing conditions. Experimental results show that inverted T-shape insulator strings have better insulation performance under icing conditions compared to ordinary suspension insulator strings (I-shape insulator strings). Analysis shows that inverted T-shape configuration leads to improvement in 50% icing flashover voltage range from 4.79% to 11.92%. Furthermore, 50% icing flashover voltage of inverted T-shape insulator strings satisfy negative power function with both freezing water conductivity and equivalence ice thickness. Results indicate that different ice morphology and flashover development process lead to the insulation improvement of inverted T-shape insulator strings. Based on the analysis on Ice Stress Parameter (ISP) and insulation improvement, some suggestions on configuration of inverted T-shape insulator strings are presented in this paper.