A lightning arrester (surge arrester) is a protective device used in substations to limit transient overvoltages caused by lightning strikes or switching operations.

Function

• •Surge protection: Diverts high-energy transients to ground
• •Equipment protection: Prevents damage to transformers, switchgear, and other equipment
• •System reliability: Ensures continuous operation during atmospheric disturbances

Types of Lightning Arresters

• •Gapped type: Traditional design with spark gaps
• •Gapless (MOV): Metal oxide varistor technology for faster response
• •Station class: Heavy-duty for substation applications
• •Distribution class: For lower voltage distribution systems

Technical Specifications

• •Rated voltage: Matched to system voltage (e.g., 220kV, 400kV)
• •Discharge current: Typically 10-20 kA rating
• •Insulation level: Coordinated with protected equipment
• •Housing: Porcelain or polymer for weather resistance

Installation Guidelines

• •Mount close to protected equipment for effective protection
• •Connect to dedicated ground conductor
• •Ensure adequate clearances per voltage level
• •Regular inspection of housing and connections