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Which of the following characteristics should the line supports for transmission lines possess?
High mechanical strength
Longer life
Low cost
All of the above
All of the above
Transmission line supports, such as steel towers or poles, serve as the physical foundation for conducting materials in a power system. To ensure grid reliability and safety, they must possess high mechanical strength to withstand various environmental and electrical forces, exhibit long operational lives, and remain economically viable for large-scale deployment.
Transmission line supports, such as steel towers or poles, serve as the physical foundation for conducting materials in a power system. To ensure grid reliability and safety, they must possess high mechanical strength to withstand various environmental and electrical forces, exhibit long operational lives, and remain economically viable for large-scale deployment.
S=8TwL2тАЛ тАФ Sag of conductor where S is sag, w is weight per unit length, L is span, and T is tension.
FSтАЛ=Working┬аTensionUltimate┬аStrengthтАЛ тАФ Factor of safety calculation for mechanical design.
The support structures are designed to manage the tension T of the conductors and the gravitational load W. They must withstand wind pressure PwтАЛ and ice loading in certain regions, requiring high material strength, usually provided by galvanized steel or reinforced concrete. Furthermore, economic considerations demand the lowest cost per unit length, balancing initial capital expenditure with maintenance costs over a typical service life of 30 to 50 years.
Supports must handle the mechanical tension exerted by conductors.
Corrosion resistance (galvanization) is critical for longer service life.
The total cost includes material, labor, and lifetime maintenance.
The height of the support is determined by ground clearance requirements.
Ensures structural integrity during extreme weather events.
Reduces downtime through high-durability materials.
Optimizes project budget for large transmission networks.
High mechanical strength often conflicts with material cost.
Extreme heights increase risk of lightning strikes.
High Voltage (HV) transmission towers
Distribution poles (wood, concrete, or steel)
Sub-transmission line structures
Materials used include steel (lattice towers), concrete (PSC poles), and wood (lower voltage distribution).
Standard Indian codes (IS 802) define the loading requirements for overhead electrical lines.
D is correct тАФ Line supports must balance mechanical strength, long-term durability, and cost-efficiency to be suitable for large-scale electrical transmission infrastructure.
Always remember that in transmission line design, the sag S is inversely proportional to tension T; higher mechanical strength in supports allows for higher tension and thus less sag, enabling longer spans.