Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
The disadvantage/disadvantages associated with overhead distribution systems is/are
Lightning Surges
Very high initial cost
Both of these
None of these
Lightning Surges
Overhead distribution systems are inherently exposed to atmospheric conditions, making them highly susceptible to lightning surges. Unlike underground cables which are shielded by the earth, overhead lines are elevated, which increases the likelihood of picking up induced or direct lightning transients that can damage insulation and equipment.
Overhead distribution systems are inherently exposed to atmospheric conditions, making them highly susceptible to lightning surges. Unlike underground cables which are shielded by the earth, overhead lines are elevated, which increases the likelihood of picking up induced or direct lightning transients that can damage insulation and equipment.
VsurgeтАЛ=ZcтАЛ├ЧIsurgeтАЛ тАФ where ZcтАЛ is the characteristic impedance of the line.
Lightning strikes create high-voltage surges that propagate along overhead transmission and distribution conductors. These surges travel at the speed of light and can exceed the Basic Insulation Level (BIL) of transformers and switchgear, leading to flashovers and dielectric breakdown of the insulation if lightning arresters are not properly coordinated.
Overhead systems have lower initial costs compared to underground systems, refuting option B.
Lightning surges cause high voltage transients leading to insulation failure.
Surge arresters (e.g., ZnO) are essential protective devices installed at distribution transformers.
Exposure to environmental factors like wind, ice, and lightning is a primary disadvantage.
Lower initial installation and material costs
Easier to locate and repair faults
Higher thermal dissipation capacity
Vulnerability to lightning surges
Susceptibility to wind and storm damage
Lower aesthetic appeal and higher maintenance overhead
Rural electrification networks
High-voltage transmission systems
Suburban overhead distribution feeders
Option B is incorrect because overhead lines are significantly cheaper to install than underground cables, which require costly excavation and specialized insulation.
Lightning arresters are placed in shunt with the equipment to divert surge energy to the ground.
A is correct тАФ Lightning surges are a major disadvantage as overhead lines remain exposed to atmospheric electrical discharges.
In competitive exams, always remember: Overhead = Low Initial Cost but High Maintenance/Vulnerability; Underground = High Initial Cost but Low Maintenance/Vulnerability.