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Examoogle • User • info@examoogle.com • EE-2024-8821
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Voltage surge occurs due to
Lightning
Switching surge
Arcing ground
All of above
All of above
Quick Summary: Voltage surges are transient overvoltages that occur in power systems due to atmospheric disturbances, sudden switching operations, or internal insulation faults. Since lightning, switching operations, and arcing grounds all contribute to high-frequency or high-magnitude transient voltage spikes, they are all valid causes of voltage surges.
Voltage surges are transient overvoltages that occur in power systems due to atmospheric disturbances, sudden switching operations, or internal insulation faults. Since lightning, switching operations, and arcing grounds all contribute to high-frequency or high-magnitude transient voltage spikes, they are all valid causes of voltage surges.
Vsurge=Ldtdi — Voltage induced due to rapid current change during switching
Vmax=Vpeak×(1+n) — Voltage escalation factor in arcing grounds
Surges represent a sudden change in electrical energy. Lightning induces direct or indirect electromagnetic pulses that travel along conductors. Switching surges occur due to the rapid change in magnetic fields (L di/dt) during breaker operations, while arcing grounds in ungrounded or resonant grounded systems cause cyclic charging of line capacitances, leading to voltage multiplication.
Lightning causes external surges (Atmospheric surges).
Switching surges are internal transients caused by operation of circuit breakers/isolators.
Arcing ground occurs in ungrounded neutral systems due to intermittent faults.
Surge protection devices like Lightning Arresters (LA) are used to divert these surges to ground.
Protection of expensive power transformers
Prevents insulation failure in transmission lines
High magnitude surges can exceed the Basic Insulation Level (BIL) of equipment
Requires complex insulation coordination
Substation insulation design
Power system transient analysis
Switching surges are generally less steep than lightning surges but can carry significant energy.
The arcing ground phenomenon is particularly severe in systems with isolated neutrals where it can cause voltage to rise up to 3-5 times the phase voltage.
D is correct — Lightning, switching operations, and arcing grounds are all distinct mechanisms that generate high-voltage transients in electrical systems.
Always remember that lightning surges are 'external' while switching and arcing grounds are 'internal' surges. Both require surge arresters for protection.