DEVELOPMENT OF ADVANCED ARRESTERS FOR GIS WITH NEW ZINC-OXIDE ELEMENTS

New zinc-oxide elements with a varistor voltage about twice that of co nventional ones of the same thickness have been developed by reducing the ZnO grain size with a new additive, which enable to halve the seri es number of elements in metal oxide surge arresters. The advanced arr esters with these elements for GIS are compact by 40 to 60 % in volume compared with conventional ones. The electrical and mechanical perfor mance of the advanced arresters was satisfactory through the various e valuation tests such as thermal stability test, residual voltage test, seismic test, long-term stability test, etc.