Overhead transmission lines are frequently stranded for multiple reasons:
1). Flexibility
2). Reduced Stress Concentration
3). Improved Current Carrying Capacity
4). Enhanced Resistance to Galloping
5). Reduction of Eddy Current Losses
1). Flexibility
Stranding makes the conductor more flexible, which makes it easier to install and able to bear bending loads during operation. This flexibility is especially significant for cables hung across large distances between transmission towers.
2). Reduced Stress Concentration
The stranding technique distributes mechanical stresses more evenly across the conductor, lowering the likelihood of stress concentrations that could cause mechanical failure, including metal fatigue or conductor elongation.
3). Improved Current Carrying Capacity
Stranding enhances the conductor’s surface area, allowing it to dissipate heat more effectively. This improved thermal performance enables the conductor to carry higher currents without exceeding its temperature rating, hence boosting current carrying capacity.
4). Enhanced Resistance to Galloping
Galloping occurs when overhead conductors oscillate owing to wind-induced vibrations. Stranded conductors are less likely to gallop than solid conductors because the various smaller strands interrupt the airflow around the conductor, lowering the aerodynamic forces that produce galloping.
5). Reduction of Eddy Current Losses
Stranding decreases eddy current losses by disrupting the continuous course of circulating currents within the conductor. This improves the transmission line’s efficiency by reducing energy losses caused by induced currents.
Overall, stranding enhances the
- Mechanical qualities,
- Thermal qualities, &
- Electrical qualities
of overhead transmission wires, making them more dependable and effective at transmitting electrical power across long distances.