arrester

Surge arresters are widely used across various electrical infrastructures, from residential circuits to large-scale utility substations. They can be found in circuit breakers within homes, inside pad-mounted transformers, on pole-mounted transformers, as well as on riser poles and high-voltage substations, effectively mitigating the risks associated with power surges.

Distribution arresters—sometimes referred to as thunder arrestors—play a crucial role in shielding electrical distribution networks from transient overvoltages and lightning-induced spikes. At their core, these devices employ metal-oxide varistors (MOV), with zinc oxide blocks that swiftly conduct excess surge current to ground. By clamping these voltage spikes to safe levels, distribution arresters protect essential assets—transformers, switchgear, and lines rated up to 72.5 kV—from costly damage.

These protective units are broadly categorized into three classes:

• Normal Duty (ND): Provides baseline surge protection in regions with infrequent lightning activity.
• Heavy Duty (HD): Designed for areas experiencing more severe or frequent storm conditions.
• Heavy Duty Riser: Incorporates larger MOV discs for maximum surge absorption, often deployed to safeguard underground cables and associated equipment.

In modern practice, you’ll also see them marketed under terms like “search arrester,” highlighting their role in pinpointing and diverting transient faults. Housings are typically fashioned from either porcelain or polymer; silicone rubber is a popular choice for polymer encasements due to its outstanding UV resistance and hydrophobic surface, which helps minimize contamination buildup and reduces maintenance requirements.

Key attributes include:

• Ultra-fast MOV chips that clamp surges within microseconds
• Multiple protection levels to match diverse system and environmental needs
• Integrated disconnector mechanisms for clear, visible failure indication
• Robust, weatherproof polymer enclosures capable of enduring harsh outdoor conditions
• Exceptional mechanical strength to withstand impacts, vibration, and environmental stresses
• Full compliance with IEEE C62.11 standards, ensuring reliability and safety

Whether termed a thunder arrestor for its lightning-focused protection or a search arrester for its fault-locating capabilities, these devices are indispensable for maintaining the integrity and longevity of distribution infrastructure.