Introduction:
While erecting an overhead line, it is very important that conductors are under safe tension. If the conductors are too much stretched between supports in a bid to save conductor material, the stress in the conductor may reach unsafe value and in certain cases the conductor may break due to excessive tension. In order to permit safe tension in the conductors, they are not fully stretched but are allowed to have a dip or sag.
Learning Objectives:
- To understand sag and its importance
- To realize how to design overhead lines by maintaining sag
Lecture Contents:
- Sag in Overhead Lines
- Calculation of Sag
(i) Supports are at equal levels and (ii) Supports are at unequal levels
- Effect of wind and ice loading
- Some Mechanical Principles
Learning Outcomes:
The students will be able to
- Design overhead lines by managing sag, tension and ground clearance
- Understand mechanical factors of safety to be used in transmission line design
