Lightning arresters are critical devices in power systems designed to protect equipment from lightning strikes and overvoltage damage. They are widely used in substations, transmission lines, and distribution networks. Their core function is to divert lightning or switching overvoltages to the ground, limiting voltage amplitudes and ensuring the safety of equipment insulation.
Working Principle
Lightning arresters utilize materials with non-linear resistive properties (e.g., metal oxide). Under normal voltage, they exhibit high resistance, allowing only minimal leakage current. When overvoltage occurs, their resistance drops sharply, rapidly discharging current and clamping the voltage within a safe range. After operation, they automatically restore to a high-resistance state, achieving "self-healing."
Main Types
Metal Oxide Arrester (MOA): The modern standard, featuring gapless design, fast response, high current-handling capacity, and long service life.
Valve-Type Arrester: Contains silicon carbide non-linear resistor discs and series gaps, often used in legacy system upgrades.
Expulsion-Type Arrester: Uses gas-generating materials to extinguish arcs, commonly applied at distribution line endpoints.
Selection and Application
Voltage Rating: Must match the system's rated voltage and continuous operating voltage (e.g., a 17kV arrester for a 10kV system).
Installation Locations: Key nodes such as substation buses, transformer terminals, and transmission towers.
Environmental Adaptability: Choose anti-pollution types for heavily contaminated areas; ensure low-temperature sealing performance in cold regions.
Maintenance Guidelines
Regularly test leakage current and insulation resistance; abnormal values indicate internal moisture or aging.
Inspect operation counters after thunderstorm seasons; frequent activations warrant performance evaluations.
Replace arresters immediately if seals fail or casings are damaged to prevent explosion risks.