Development of a 500 kV transmission line arrester and its characteristics

A 275 kV gapped type arrester was developed and tested on an EHV transmission line which is liable to be extensively affected once a line fault occurs. The study was followed by the development of a 500 kV gapped type arrester, and its field test on an existing line was started in September 1990. The main characteristics of the 500 kV gapped type arrester are discussed, and evidence to corroborate its applicability to 500 kV transmission lines is presented. The series gap length was reduced by adopting an optimal electrode configuration and a reasonable concurrence probability of the arrester unit and a switching impulse, in order to design the practicable gapped type arrester for existing 500 kV transmission towers. It was demonstrated that the 500 kV gapped type arrester can be depended upon to cut off the follow current even when it is contaminated. Satisfactory insulation coordination with the existing insulator assemblies was demonstrated. >