Studies on Corona Performance of Insulator Assemblies for UHV Transmission Lines

This paper describes the results of a series of investigation into corona performance of proto type insulator assemblies for UHV transmission lines. For the shielding rings of UHV insulator assemblies, satisfactory RIV characteristics under wet condition was found not to be obtained by simply extrapolating the design practice of EHV insulator assemblies. By the best use of the shielding function of conductors, if relatively small shielding rings are installed at the energized end of the insulator string, the RIV can be restricted below a target value. The insulator assemblies equipped with such shielding rings showed a satisfactory performance from AN point of view.