What Is a High Speed Concentric Stranding Line and Why It’s Essential for HV & EHV Power Cable Manufacturing?

As global demand for high voltage (HV) and extra-high voltage (EHV) power cables continues to rise, manufacturers are turning to more efficient, high-precision solutions to keep up with market needs. One of the most essential technologies enabling this production is the High Speed Concentric Stranding Line — a specialized cable-making machine designed for producing both overhead and insulated AC/DC power conductors with high precision and productivity.

 What Is a High Speed Concentric Stranding Line?

A High Speed Concentric Stranding Line is an advanced cable manufacturing system designed for the stranding of large copper or aluminum conductors, including Milliken and compacted round or trapezoidal wires. It is widely used in the production of high voltage (HV) and extra-high voltage (EHV) cables that power critical energy infrastructure across the globe.

The stranding process uses a no-back-twist concentric method, ensuring excellent conductor alignment, reduced cable deformation, and improved current-carrying capacity — essential for long-distance and high-load power transmission.

 Key Features:

• Application: Suitable for AC cables using Milliken conductors and DC cables with large round or trapezoidal compacted conductors

• Cage Speed: Up to 500 RPM

• Stranding Pitch: 40–350mm (Stepless adjustable)

• Stranding Structure: Concentric design with front & rear support, flying wing system, wire separation, and bobbin storage

• Motorization: Each component (cage, storage bobbin, traverse system) driven by independent variable frequency motors

• Wire Rewinding: Individual wires rewound to bobbins via external payoff system with separate motorized traverse

 Key Advantages:

1. High Efficiency with Minimal Centrifugal Force
   Thanks to the concentric cage structure, the rotation center aligns with each bobbin’s center, minimizing centrifugal force and allowing for higher rotational speeds and faster stranding.

2. Large Capacity Bobbin Storage
   Reduces the frequency of loading/unloading, significantly lowering labor intensity and increasing uptime.

3. Streamlined Wire Handling
   Once the storage bobbin is emptied, single wire can be rewound directly from the drawing process, minimizing intermediate steps and saving time.

4. Stable and Adjustable Tension
   Cage tension is independent of cage speed, offering precise control during the entire stranding process.

5. Low Maintenance Design
   With fewer wear-prone components and a compact mechanical structure, the system ensures long-term reliability and reduced maintenance costs.