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Multicore cables generally use
Square conductors
Rectangular conductors
Sector-shaped conductors
Circular conductors
Sector-shaped conductors
Multicore cables, especially those used for higher voltage levels (above 1.1 kV), utilize sector-shaped conductors to minimize the overall cable diameter. By shaping the conductors into segments of a circle, the cross-sectional area is better utilized, reducing the amount of insulation and sheath material required.
Multicore cables, especially those used for higher voltage levels (above 1.1 kV), utilize sector-shaped conductors to minimize the overall cable diameter. By shaping the conductors into segments of a circle, the cross-sectional area is better utilized, reducing the amount of insulation and sheath material required.
A=4╧АD2тАЛ тАФ Basic area calculation for circular conductors (reference)
VspaceтАЛ=VtotalтАЛтИТтИСVconductorsтАЛ тАФ Interstitial space reduction principle
In a circular conductor multicore cable, a large portion of the space between conductors remains unfilled, leading to a larger total cable diameter and increased material cost. Sector-shaped conductors are essentially circular cross-sections divided into segments (like a pie chart), which nest together tightly. This reduces the interstitial space and the total circumference, thereby decreasing the amount of dielectric, bedding, and armor material needed, resulting in a more compact and economical design.
Reduces cable overall diameter and weight.
Commonly used for voltages up to 11 kV.
Saves on insulating material and lead/aluminum sheathing costs.
Sector shape is typically 120 degrees for 3-core cables.
Lower material costs due to reduced diameter
Easier handling due to reduced overall weight
Optimized space utilization in ducts
Higher electrical stress at the corners of the sectors
Complex manufacturing process compared to simple drawing of circular wires
Underground distribution power cables
Industrial power supply installations
For voltages above 11 kV, circular conductors are preferred because the sharp edges of sector-shaped conductors can cause high electric field concentration and potential insulation breakdown.
Options A and B (Square/Rectangular) are inefficient due to poor filling factors and high electric stress at corners.
C is correct тАФ Multicore cables use sector-shaped conductors to reduce the volume of insulation and overall cable dimensions by minimizing interstitial spaces.
Always remember that while sector-shaped cables save costs, circular conductors are superior for High Voltage (HV) applications to avoid field concentration at the conductor edges.