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Which portion of the transmission system is more prone to faults?
Alternator
Transformer
Overhead lines
Underground cables
Overhead lines
Overhead transmission lines are the most vulnerable component of a power system due to their exposure to atmospheric conditions ┬╖ Unlike transformers or generators, which are enclosed and protected, overhead lines span vast distances and are directly subjected to environmental hazards.
Overhead transmission lines are the most vulnerable component of a power system due to their exposure to atmospheric conditions ┬╖ Unlike transformers or generators, which are enclosed and protected, overhead lines span vast distances and are directly subjected to environmental hazards.
PfaultтАЛтИЭL
Where L is the length of the transmission line, showing that fault probability increases with distance.
The susceptibility of overhead lines to faults is primarily due to their open design ┬╖ Factors include lightning strikes, tree contact, bird faults, insulator flashovers caused by pollution or salt spray, and physical mechanical damage due to storms or vibrations ┬╖ Because they are not enclosed, these external events frequently trigger phase-to-ground or phase-to-phase faults.
Overhead lines account for approximately 80% to 90% of all power system faults.
Most faults on overhead lines are transient or temporary in nature (e.g., lightning strikes).
Transformer and alternator faults are generally permanent and require immediate disconnection and repair.
Underground cables are protected from weather but suffer from insulation breakdown due to thermal stress or aging.
Overhead lines allow for easier fault location due to visual inspection.
Faults in overhead lines are often self-clearing or transient.
High exposure to environmental elements.
Maintenance is required over large, often inaccessible geographical areas.
Long-distance bulk power transmission.
Rural electrification networks.
Option A (Alternators) and B (Transformers) are 'static' or 'rotating' equipment located within substations, making them less prone to external environmental faults.
Option D (Underground cables) are much less likely to have faults than overhead lines, but when they do, they are almost always permanent and much harder to locate and repair.
C is correct тАФ Overhead lines are the most fault-prone part of the system because they are exposed to the environment and cover large distances.
Always remember: overhead lines = high transient faults; cables/transformers = low frequency but high severity (permanent) faults.