Development of 500kV Externally Gapped Line Arrester Transmission Lines

摘要

Metal-oxide surge arresters with external gaps can eliminate the need of countermeasures against swithching overvoltage or the deterioration of ZnO disks, and effectively improve the reliability of transmission systems. This paper discusses the structure optimization for the two discharging electrodes of the external gap in order to improve the lightning protection performance of the line surge arrester. Experimentally, the line surge arrester with the optimally external gap is found to have high switching impulse overvoltage withstanding performance. Moreover, the insulation coordination performance at the steep lightning overvoltage and the follow current interrupting performance under the artificial pollution condition are also experimentally verified.