Mechanical design of overhead lines

What is the purpose of the shield wire in overhead lines?

• A. To provide a path for lightning
• B. To carry the load
• C. To connect the insulators
• D. To provide insulation

Which type of pole is preferred for transmission lines in urban areas?

• A. Steel poles
• B. Wooden poles
• C. Concrete poles
• D. All of the above

Which of the following is not a factor that influences the choice of conductor size in overhead lines?

• A. Load current
• B. Ambient temperature
• C. Distance between supports
• D. Emissivity of the conductor

What is the maximum permissible sag for conductors in transmission lines?

• A. 10% of the span
• B. 15% of the span
• C. 20% of the span
• D. 25% of the span

Which of the following is not a type of vibration experienced by overhead conductors?

• A. Aeolian vibration
• B. Galloping vibration
• C. Earthquake vibration
• D. Sub-span oscillation

Which type of insulator is used for high voltage transmission lines?

• A. Pin-type insulator
• B. Suspension insulator
• C. Shackle insulator
• D. Stay insulator

Which of the following is not a material used for overhead line conductors?

• A. Aluminum
• B. Copper
• C. Steel
• D. Zinc