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Examoogle • User • info@examoogle.com • EE-2024-8821
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In power system nearly 50% of faults occurs in
Overhead line
Transformer
Generator
Switchgear
Overhead line
Quick Summary: Overhead transmission lines are the most vulnerable component of a power system as they are exposed to harsh atmospheric conditions and external environments. Statistics indicate that approximately 50% to 60% of all power system faults occur on overhead lines, primarily due to their extensive length and exposure.
Overhead transmission lines are the most vulnerable component of a power system as they are exposed to harsh atmospheric conditions and external environments. Statistics indicate that approximately 50% to 60% of all power system faults occur on overhead lines, primarily due to their extensive length and exposure.
Ftotal≈∑FOHL+∑FEquipment — Total fault occurrences in the system.
The high failure rate is attributed to constant exposure to natural phenomena like lightning strikes, storms, high winds, and falling trees. Unlike equipment inside substations or power plants (transformers, generators, switchgear), which are housed in controlled environments, lines span vast distances through uncontrolled terrain where insulation breakdown or physical damage frequently triggers faults.
Overhead lines have the highest exposure to transient faults like lightning and bird strikes.
Transformers, generators, and switchgear are located in protected or semi-protected environments.
Most overhead line faults are transient and can often be cleared by auto-reclosure.
Fault distribution: OHL (50-60%) > Switchgear (15-20%) > Transformer (10-15%) > Generator (5-10%).
Overhead lines allow for easier fault detection via distance relaying.
Most faults are self-clearing or transient, allowing for successful auto-reclosure.
High vulnerability to weather conditions and physical hazards.
Difficulty in patrolling and repairing faults in remote locations.
Option B (Transformer) is incorrect; while critical, it is protected in substations.
Option C (Generator) is incorrect; generators are enclosed in high-security, climate-controlled environments.
Option D (Switchgear) is incorrect; these are specifically designed to isolate faults, not be the primary location of them.
A is correct — Overhead lines are the most vulnerable to faults due to their vast exposure to the open environment.
Always remember that fault frequency is inversely proportional to the level of enclosure or environmental protection an asset has.