Many people think that the steel core inside ACSR is used for conducting electricity. In fact, on the contrary, steel cores hardly transmit electricity.
This article uses the simplest logic to explain the true function of steel cores, helping you to select and connect with overseas power projects more accurately.
ACSR steel cored aluminum stranded wire is the most commonly used wire in overhead transmission lines.
Many people have been puzzled by the structure: why does the manufacturer have to add a steel core in the middle when the outer aluminum wire is already sufficient?
Many people even mistakenly believe that steel cores are used to enhance conductivity.
Today, we will thoroughly explain the design logic of ACSR steel core in a simple and straightforward way.
1. First understand: The advantages and disadvantages of aluminum and steel complement each other
The advantages of pure aluminum wire are very obvious: good conductivity, light weight, and low transmission loss, making it very suitable as a power transmission material.
But it has a fatal weakness: it is too soft and has extremely poor tensile strength.
If only pure aluminum stranded wire is used as an overhead line, with a slightly larger span, the wire will seriously fall and deform, and it is also easy to break directly in strong winds and icy weather.
Steel, on the other hand, is exactly the opposite: it has poor conductivity and is heavy, but it has extremely strong tensile strength and is very sturdy.
So engineers designed the ACSR composite structure: the outer layer of aluminum is responsible for conductivity, and the inner steel core is responsible for stress, perfectly combining the advantages of the two materials.
2. The Four True Core Functions of ACSR Steel Core
① Undertake the main tensile force to prevent wire breakage
An overhead line is suspended between iron towers. The weight of the wire, wind pulling, and winter icing can all generate significant tensile forces. Most of the tension in the entire cable is borne by the central galvanized steel core.
Without a steel core, pure aluminum wire cannot support long-distance overhead laying.
② Control sag and increase span
Sag is the amplitude of the drop in the middle of a wire. The pure aluminum wire falls very seriously, and the tower must be erected very densely, resulting in extremely high engineering costs.
Steel core can significantly increase the overall tension, making the wire flatter and with less sag.
With steel cores, power poles/towers can be pulled further, making the project more cost-effective.
③ Enhance wind resistance, ice resistance, and vibration resistance
The outdoor route is exposed to harsh weather all year round. Strong winds swaying and snow and ice covering will continue to wear and pull the wires.
The presence of steel cores makes the entire wire structure more stable, less likely to deform or break, and greatly improves its outdoor service life.
④ Galvanized anti-corrosion, long-term stable operation
ACSR steel cores are all hot-dip galvanized, which can effectively prevent rust and oxidation. Even with long-term outdoor use, the internal structure can maintain stable mechanical properties and will not easily age or fail.
3. Why choose ACSR for high-voltage long-distance projects?
Compared to pure aluminum stranded wire AAC, ACSR has very good advantages:
Less likely to break under the same span
Smaller sag, safer and more stable line
Stronger weather resistance, suitable for complex environments in mountainous areas, rivers, and wilderness
The overall project cost is lower, suitable for long-distance transmission of high voltage and ultra-high voltage
Skype: verdecable