Development and Tests of a 220 kV Novel Composite Insulator with Lightning Protection and Icing Flashover Prevention

Metal-oxide surge arresters and anti-icing insulators are widely used in transmission lines to prevent lightning and icing flashover, respectively. However, these two technologies have the disadvantage of single function, and sometimes surge arresters could be difficult to install because of their structural size mismatch with the tower cross arms. In this study, a 220 kV novel composite insulator with lightning protection and icing flashover prevention (CI/LP&IFP) is developed. By experimental research, the air gap distance between grading rings are obtained, the specification and number of zinc oxide (ZnO) varistors, the creepage distance and the sheds configuration of the 220 kV CI/LP&IFP are designed. Lighting and switching impulse discharge characteristics, and icing flashover characteristics are studied using experimental methods to validate the lightning protection and icing prevention performance. Test results indicate that, the designed air gap distance of 880±10 mm can ensure that the 220 kV CI/LP&IFP is discharged under a lightning over-voltage of more than 900 kV and would not be discharged under switching and power frequency overvoltages. When the icing thickness is 12.8 mm, the icing flashover voltage gradient of the 220 kV CI/LP&IFP is 14.57% more than that of the 220 kV conventional composite insulators. Results in this study can give help to the flashover performances improvement of transmission lines in heavy lightning and icing regions.