- Stranded Conductors Definition: A stranded conductor consists of several thin wires called strands, making it flexible and suitable for electrical power systems.
- Transmission and Distribution: Stranded conductors are crucial for transmitting and distributing electricity over long distances.
- Construction: Typically, these conductors have a steel core for strength and aluminum strands for conductivity.
- Stranding Process: Strands are twisted together in layers, with each layer twisted in opposite directions for added flexibility.
- Flexibility: The flexibility of stranded conductors increases with the number of strands, making them easy to transport.
Stranded conductors are widely used in electrical power systems for transmission and distribution lines. A stranded conductor consists of several thin wires of small cross-sectional area called strands.
As shown in figure above, at the center of stranded conductor, we are using steel conductor which provided the high tensile strength to conductor. In the outer layers of stranded conductor, we use aluminum conductors, which provide the conductivity to stranded conductor.
The main reason for using stranded conductors is flexibility. A single solid conductor lacks flexibility and is hard to coil, making it difficult to transport over long distances. Using several thin wires, called strands, forms a stranded conductor. This flexibility makes it easy to coil and transport.
Facts about Stranded Conductor
There are some facts to be noted about stranded conductors-
- The stranded conductor is having sufficient flexibility, which makes stranded conductor suitable to be coiled easily to transport it over long distance.
- For a stranded conductor of same cross sectional area, the flexibility of conductor increase with increase of number of strands in conductor.
- The stranded conductor is formed by twisting the strands together in layers.
- The strands of each layer are laid in helical fashion over the preceding layer. This process is called stranding.
- Generally, in successive layer, the stranding is done in opposite direction to preceding layer. This mean, if the strands of one layer are twisted in clockwise direction, the strands of next layer will be twisted in anticlockwise direction and so on ‘x’ is number of layers in conductor.
- Generally, the total number of strands in any conductor is given by the formulae of,
Where, N is total number of strands in stranded conductor. - Generally the diameter of conductor can be calculated by using the formula of,
Where, D is the diameter of conductor,
‘d’ is the diameter of each strand.
Table Representing the Number of Strands, Diameter and Cross-Sectional view of Stranded Conductor for Different no. of Layers
| Sl No. | No. of layers ‘x’ | Total no. of strands N = 3x2 – 3x + 1 | Diameter of conductor D = (2x – 1)d | Cross Sectional View of Stranded Conductor |
| 1 | 1 | 1 | d |  |
| 2 | 2 | 7 | 3d |  |
| 3 | 3 | 19 | 5d |  |
| 4 | 4 | 37 | 7d |  |
| 5 | 5 | 61 | 9d |  |
