Lightning Arrester (Surge Arrester)
A protective device diverting high-voltage surges from lightning and switching to ground, safeguarding transformer insulation.
A lightning arrester (surge arrester) protects transformer insulation by diverting overvoltage surges to ground when voltage exceeds a protective level. Essential for BIL coordination.
Modern arresters use zinc oxide (ZnO) varistor blocks with excellent nonlinear V-I characteristics—high impedance at normal voltage, conducting at overvoltage—without series gaps.
Selection criteria: rated voltage, protective level (below transformer BIL with margin), energy absorption capability, altitude correction.
QDTB recommends and coordinates arrester selection for all transformer installations. HV switchgear and prefabricated substations include integrated surge protection.
Related Products
Related Terms
BIL (Basic Impulse Level)
The ability of transformer insulation to withstand high-voltage surges from lightning or switching, measured in kV peak.
Dielectric Strength
The maximum electric field an insulating material can withstand before breakdown, measured in kV/mm.
Lightning Impulse Test
A high-voltage test simulating lightning surges to verify transformer insulation withstands transient overvoltages.
More Terms Starting with “L”
Load Tap Changer (LTC)
A mechanism allowing transformer tap ratio changes while energized and under load for real-time voltage regulation.
Leakage Reactance
Reactance from magnetic flux not linking both windings, a major component of transformer impedance.
Loss Evaluation
A financial methodology assigning monetary value to transformer losses for optimal lifetime economic selection.
Lightning Impulse Test
A high-voltage test simulating lightning surges to verify transformer insulation withstands transient overvoltages.
More in “Protection & Monitoring”
Buchholz Relay
A gas-actuated protective relay between transformer tank and conservator detecting internal faults by sensing gas accumulation.
Network Protector
An automatic switching device on secondary network systems preventing reverse power flow from distributed generation sources.
Relay Protection (Transformer)
Protective relay schemes detecting transformer internal and external faults, initiating circuit breaker tripping to isolate faults.
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