Gas-insulated surge arrester 3ES9 for metal-enclosed switchgear (GIS), part of the 72.5–800 kV AC/DC GIS arrester range

• Surge arrester family for gas-insulated switchgear (GIS) — listed as '3ES9 GIS' in the official product hierarchy under Gas-Insulated Arresters (3ES/T/Y), alongside the 3EY5/3EY6 clean-air arresters
• Part of the GIS arrester range covering AC/DC system voltages from 72.5 kV up to 800 kV (Portfolio of Surge Arresters & Composite Insulators, GIS & HVDC/FACTS section)
• Installs inside the earthed, gas-tight metal enclosure of the switchgear rather than in open air, limiting lightning and switching overvoltages to protect GIS bays and connected equipment
• From the arrester program manufactured in Berlin, Germany and Wuxi, China since 1925 — a type-tested portfolio according to IEC and IEEE standards
• Detailed electrical ratings (Ur, Uc, In, energy handling) and dimension drawings for 3ES9 are available on request