Types of Conductors

Aluminium Conductors have completely replaced copper conductors because they are cheaper and lighter, and have similar resistance.

Aluminium Conductors are used in Transmission and Distribution systems to carry electrical energy from generating stations to end users. The major difference between different types of conductors (listed below) lies in the materials used to manufacture them.

India plans to invest ~USD 1 trillion by 2030 in the power sector to achieve its goal of providing 24/7 electricity to all citizens. This will generate enormous demand for power conductors in India.

Types of Aluminium Conductors Used

  • AAC Conductors, i.e. All Aluminium Conductors
  • AAAC Conductors, i.e. All Aluminium Alloy Conductors
  • ACAR Conductors, i.e. Aluminium Conductor Alloy Reinforced Conductors
  • ACSR Conductors, i.e. Aluminium Conductor Steel Reinforced Conductors
  • ACSR/AW Conductors, i.e. Aluminium Conductor Aluminium Clad Steel Reinforced Conductors
  • AACSR/AW Conductors, i.e. Aluminium Alloy Conductor Clad Steel Reinforced Conductors
  • AACSR Conductors, i.e. Aluminium Alloy Conductor Steel Reinforced Conductors

 

Types of New Generation Alloy Conductors Used

  • High Conductivity Alloy Conductors
    (including but not limited to)

    • AL 59 Conductors
    • AL-57 Conductors
    • AAAC 1120 Conductors
  • High Temperature Thermal Resistant Alloy Conductors
    (including but not limited to)

    • ACSR Conductors
    • TACSR/AW Conductors
    • STACIR/AW Conductors
    • TACSR/TW Conductors
  • High Temperature Low Sag conductors
    (including but not limited to)

    • ACSS Conductors
    • ACSS/TW Conductors
    • GZTACSR/GTACSR Conductors

 

Brief History

For over one-hundred years, electricity was delivered to consumers using bare overhead conductors that were made of conductive aluminum strands, often wrapped around a core that consisted of steel wires, popularly known as ACSR. All Aluminium Alloy Conductors (AAAC) were introduced in this category in last 10-12 years’ period.

As demand for electricity grew and new sources of generation were introduced, many transmission and distribution lines became thermally constrained due to increase in temperature on account of increased electrical current (aluminum wires when heated above 95° C begin to anneal and lead to significant Power T&D losses).

New generation conductors, or High Performance Conductors (HPC), were developed to uprate transmission and distribution corridors. HPCs are capable of withstanding temperatures of up to 250°C and can carry up to twice the power within the same corridor.

HPC Conductors – Categories

  • High Temperature Low SAG Conductors (HTLS)
    HTLS conductors can carry double or more power in existing T&D corridors while maintaining the same sag.

 

  • Special Conductors
    Special conductors are capable of carrying 25-30% more power with low T&D losses, and are suitable for replacing ACSR /AAAC Conventional Conductors in new lines, making the Transmission system more robust and future ready to meet additional power requirements in the same corridor.

 

Types of HTLS Conductors

  • Thermal Conductors comprising INVAR Core
  • GAP Conductors
  • Carbon Composite Core
  • ACSS Conductors

 

Types of HTC Conductors

  • TACSR Conductors
  • AL-59 Type Conductors

 

The latest generation conductors help reduce line losses when run at comparable temperatures to ACSR. They can reduce the 12R (major portion of technical) line losses by 25-40% compared to conventional conductors of the same diameter and weight under equal load conditions. The payback for the investment in this new technology is between 2 – 8 years, which is quite attractive, considering that their life is usually at least 35 years.

 

List of Conductors

List of Different Types of Conductors With Ratings & Characteristics

 

Types of Conductors Ratings Characteristics Remarks
AAC (All Aluminium Conductors) Up to 80°C Conductor ranging from cross-sectional area from 15 mm² to 1700 mm² with maximum construction of 126 wires in conductor. Basic features of AAC conductors: 1. High current carrying capacity 2. Suitable for low & medium voltage line in urban areas. 3. Excellent corrosion resistance 4. Ideal for use in coastal areas Concentrically stranded conductors with one or more strands of hard drawn aluminum wires.
    ACSR (Aluminium Conductor Steel Reinforced)     Up to 75°C     Conductors ranging from cross-sectional area from 15 mm² to 1750 mm² with maximum construction of 126 wires with various combination of Steel & Aluminium proportion Basic features of ACSR conductors: 1. High Tensile Strength. 2. Better Sag Properties. 3. Economic Design. 4. Suitable for remote application involving long span.         Concentrically stranded conductors with one or more layers of hard drawn aluminum wires on a core of galvanized steel wire.
AAAC (All Aluminium Alloy Conductors), Up to 85°C Conductors ranging from cross-sectional area from 15 mm² to 1700mm² with maximum construction of 126 wires in conductor. Basic features of AAAC conductors: 1. High strength to weight ratio 2. Better sag characteristics 3. Improved electrical properties 4. Excellent corrosion resistance. 5. Lighter than ACSR, with lower losses & excellent corrosion resistance. Made of high strength aluminum-magnesium-silicon alloy.
AACSR (Aluminium Alloy Conductor Steel Reinforced Conductors) Up to 85°C Conductors with cross-sectional area ranging from 15 mm² to 1750 mm², with maximum construction of 126 wires with various combination of steel & aluminum alloy proportion in conductor. Basic features of AACSR conductors: 1. Optimal strength for line design 2. Improved strength to weight ratio 3. Ideal for extra-long spans and heavy load conditions. 4. Excellent corrosion resistance. 5. AACSR conductors have ~40-60% more strength than stranded ACSR, with only 8-10% decrease in conductivity. Concentrically stranded conductors, made of one or more aluminum-magnesium-silicon alloy wire layers stranded with a high strength zinc coated (galvanized) steel core wires.
ACAR (Aluminium Conductor Alloy Reinforced Conductors) Up to 85°C Conductors with cross-sectional area ranging from 15 mm² to 1750 mm², with maximum construction of 126 wires with various combinations of aluminium & aluminium alloy. Basic features of ACAR conductors: 1. Improved strength to weight ratio 2.Improved mechanical properties. 3. Improved electrical properties 4. Excellent corrosion resistance Concentrically stranded aluminum wires of high strength aluminum- magnesium-silicon alloy (AL-MgSi) core.
ACSR/AW or ACSR/AS (Aluminium Conductor Aluminium Clad Steel Reinforced Conductors) Up to 85°C Conductor with cross-sectional area ranging from 13 mm² to 1750 mm², with maximum construction of 126 wires with various combinations of aluminum and aluminum clad steel wires in conductor. Basic features of ACSR/AW ACSR/AS conductors: 1. Good mechanical properties 2.Improved electrical characteristics. 3. Excellent corrosion resistance. 4. Better sag properties.     Concentrically stranded conductors with one or more layers of hard drawn aluminum wire on aluminum clad steel core
AL 59, AL-57 & AAAC 1120 (High Conductivity Alloy Conductors) Up to 95°C equivalent to ACSR in terms of cross sectional area provides ~25-30% more Current Ratings.   Conductors ranging from cross-sectional area from 31 mm² to 910 mm² with maximum construction of 126 wires in conductor. Basic features: 1. Better conductivity, so better power transmission 2. Lower operating cost due to lower ohmic losses 3.Can be recycled easily These are concentrically stranded conductor with one or more layers of High conductivity Al-Mg-Si alloy wires.
TACSR, TACSR/AW, TACSR/MA High Temperature Thermal Resistant Alloy conductors. Up to 150°C conductors, equivalent to ACSR in terms of cross sectional area provides ~50-60% more Current Ratings. Conductors with cross-sectional area ranging from 15 mm² to 1750mm², with maximum construction of 126 wires with various combination of aluminium & aluminium clad steel or Mischmetal coated steel proportion in conductor. Basic features: 1. Can operate at up to 150°C with specified strength loss. 2. Can carry 50-60% more current than ACSR of same size 3. For uprating lines, no modification or reinforcement is required to existing towers     High ampacity conductors with an inner core made of galvanized steel/AL clad steel/Mischmetal coated steel, and outer layer composed of thermal resistant aluminum wires.
ACSS and ACSS/TW Aluminum conductor Steel Supported. Up to 200°C conductors, equivalent to ACSR in terms of cross sectional area; provide Current Ratings of up to 200%. Conductors with cross-sectional area ranging from 15 mm² to 1750 mm², with maximum construction of 126 wires with various combination of steel & aluminium proportion in conductor. They have round wires or trapezoid shaped annealed aluminium wires. Basic features of ACSS & ACSS/TW Conductors: 1. Can operate at up to 200°C with specified strength loss 2. Lower sag than conventional composite conductors 3. Excellent self-damping characteristics; the final sag is not affected by creep     It is constructed using fully annealed aluminum wires in a round or trapezoidal shape, stranded over a core of galvanized steel/ AL clad steel/Mischmetal coated steel wires.
STACIR/AW High Temperature Super Thermal Resistant Alloy Conductors Up to 210°C Conductors, equivalent to ACSR in terms of cross sectional area; provide ~200- 250% more Current Ratings. Conductors with cross-sectional area ranging from 15 mm² to 1750 mm², with maximum construction of 126 wires, with various combinations of Al clad Invar steel & super thermal resistant aluminium alloy proportion. They have round wires or trapezoid shaped STAL wires. Basic features of STACIR/AW conductors: 1. Can operate at up to 210°C with specified strength loss. 2. Lower sag than conventional composite conductors. 3. Final Sag not affected by creep. High temperature, low sag conductors composed of round or trapezoid shaped super thermal resistant aluminium alloy wires stranded over inner core of Al cladded Invar steel wires.
GZTACSR GAP-Type Super Thermal Resistant Aluminum Alloy Conductors, steel reinforced. Up to 210°C Conductors, equivalent to ACSR in terms of cross sectional area; provide ~200-250% more Current Ratings. Conductors with cross-sectional area ranging from 50 mm² to 1750 mm², with maximum construction of 126 wires with various combinations of steel & super thermal resistant aluminium alloy proportion.     These conductors have round or trapezoid shaped STAL wires. The gap between the first layer of STAL and steel core is filled with high temperature grease with a drop point of 300°C & above. Basic features: 1. Can be tensioned on the steel core alone during erection. 2. Low sag properties above the erection temperature & good strength below thermal knee-point. 3. Suitable for continual operations at elevated operating temperatures of up to 210°C without affecting mechanical properties. 4. Reduced cost due as no expansion material is required.     High temperature low sag conductors composed of round or trapezoid-shaped super thermal resistant Aluminium alloy wires stranded over inner core of Galvanised / Al Cladded Steel wires.   The conductors have a special gap between the (high strength) steel core and (thermal resistant) AL-Zr alloy conductive layers, filled with grease.
ACCC® Aluminum Conductor Composite Core Up to 180°C Conductors, equivalent to ACSR in terms of cross sectional area; provide 200% more Current Ratings. Conductors with cross-sectional area from 155 mm² to 1451.2 mm². Proprietary product manufactured under license from CTC Global USA. Basic features of ACCC Conductors: 1. Superior strength to weight ratio 2. Low coefficient of thermal expansion allows additional electrical current 3. Increased thermal capacity with 30-40% reduction in losses These are high ampacity low sag conductors, consisting of a carbon composite core encased in protective fiberglass sheath that is helically wrapped with conductive annealed aluminum strands.
GSW Earth wire, Stay wire, Guy wires, Spaces Cables, etc. Used as specific application on transmission lines and towers. Conductors with 3-61 wire strands, with tensile grades of 350 N/mm² to 1800 N/mm².