From what we know, aluminum is a lightweight material and very easy to work with as a cable material while steel is superior in strength and has better mechanical support. These two materials are perfectly combined in the ACSR (Aluminum Conductor Steel Reinforced). Next we’ll read more about its type and its advantages in applications.
What is ACSR conductor?
ACSR conductor is a kind of high capacity and high strength stranded conductor used in overhead transmission lines. ACSR cable consists of two main components: aluminum and steel.
Steel Core: It is located in the center of the conductor and uses galvanized steel wire to enhance the mechanical strength of the wire. The steel core can be solid or twisted. The construction of the steel core may consist of a single, 7 or 19 galvanized steel wires, depending on the strength required and the application.
Stranded aluminum wire: The steel core is surrounded by multiple layers of aluminum wires that are twisted concentrically to form a continuous outer layer. The choice of aluminum allows the ACSR to reduce energy losses when transmitting large amounts of power. The number of stranded aluminum wires and the number of wires per layer can be adjusted according to the current load-carrying requirements.
ACSR exists in a number of different conductor configurations for steel stranded wire and aluminum stranded wire. So in the early days of the wire and cable industry various animal names were used as species and ACSR conductor size identifiers. For example:
ACSR Dog conductor typically consists of six 4.72 mm diameter aluminum strands and seven 1.57 mm diameter steel strands.
ACSR Rabbit conductors typically consist of 6 aluminum strands with a diameter of 3.35 mm and 1 steel strand with a diameter of 3.35 mm.
ACSR Conductor- Common Types
In order to adapt to a variety of applications and performance requirements, more and more ACSR conductor types have emerged in the market, providing users with more flexible and diverse choices. Likewise, the following types of overhead cables are available from ZW Cable:
All Aluminium Conductor –AAC
AAC conductor has a unique all aluminium structure and is made by concentric winch process. The conductor structure is pretty easy, efficient and has high conductivity. Compared with ACSR, AAC may be inferior in strength. However, it performs well in cost-effectiveness, portability and ease of maintenance, especially for low to medium voltage overhead lines and flexible electrical wiring systems.
All Aluminium Alloy Conductors –AAAC
AAAC is made of high-performance aluminum-magnesium-silicon alloy by precise multi-layer stranding process. Compared with traditional AAC, AAAC cable has better tensile strength and weight ratio under the same diameter, which is especially advantageous in long distance transmission.
Aluminium Conductor Aluminium Reinforce –ACAR
ACAR cable uses high strength aluminum alloy core wrapped with aluminum wire concentric layer. ACAR differs from AAC and AAAC in that it uses alloy cores to enhance its performance in overhead transmission and distribution networks, including strength and current carrying capacity.
Aluminium Conductor Steel Reinforced – ACSR
ACSR conductor is wrapped in multi-layer aluminum wire with steel filling core. This is designed for high strength applications. This type of conductor is suitable for overhead grounding lines, as well as installations requiring extra-long spans and river crossings. Unlike Aluminum Conductor Steel Support (ACSS), which relies on a steel core to maintain its strength at varying temperatures, ACSR conductors excel even at high and low temperatures thanks to the high strength of their steel core and the excellent current-carrying capacity of aluminum.
ACSR Conductor– Main Advantages
Why are ACSR conductors specifically chosen for overhead lines? The reason being that overhead transmission requires a conductor that is capable of meeting the needs of a wide variety of applications. Aluminum Conductor Steel Reinforced (ACSR) cables are uniquely suited to meet these diverse requirements.
Weight advantage: aluminum is about one-third the density of steel and ACSR cables are lighter than all-steel or all-aluminum cables with the same conductivity. If a typical high-voltage transmission line uses an all-aluminum conductor, it may need a thicker cross-section or a denser support structure to withstand its own weight and wind. On the other hand, ACSR can achieve this with a smaller diameter and a longer distance between towers, significantly reducing the cost of tower and foundation construction.
High tensile strength: the steel core provides additional strength to the cable to better support its own weight and reduce sag, making it ideal for crossing complex terrain such as rivers and valleys.
High electrical conductivity: the aluminum coating provides good electrical conductivity, ensuring efficient power transmission with minimal loss, contributing to overall energy efficiency.
Corrosion Resistance: although the steel core itself easy to rust, but after galvanizing or other anti-corrosion process, and then with the natural protection of aluminum, ACSR cables exhibit excellent corrosion resistance in the general atmosphere and in non-extreme corrosive environments and maintain long service life even under harsh conditions.
Convenient installation and maintenance: ACSR cable not only strong structure, relatively light weight, more time-saving installation and labor-saving. In addition, its flexibility allows it to easily adjust its shape to suit different overhead line configurations and is more convenient for maintenance.
Economy: because the price of aluminum is relatively low, ACSR cable is very competitive in cost, the overall cost of lines reduced.
ACSR conductor- Widespread applications
ACSR conductor is widely used in power transmission industry in various countries. Here are some concrete examples:
Across large bodies of water. A typical example is the Earl Strait Bridge, which connects Denmark and Sweden. It adopts ACSR cable in overhead transmission system. The application is critical to maintaining power connections between the two countries and demonstrates the ability of ACSR to travel long distances on water.
High-voltage power transmission in China. China’s UHVDC (ultra high voltage direct current) transmission lines, such as the Xiangjiaba-shanghai line, use ACSR conductors in segments requiring high load and strength. These lines transmit power over thousands of kilometers, highlighting the suitability of ACSR for long-distance and high-voltage applications.
Urban and rural distribution networks. Although ACSR is more relevant for long-distance transmission, it is also used for distribution networks in urban and rural areas. For example, overhead lines that power suburban or remote farmhouses often use ACSR conductors to ensure their reliability and cost-effectiveness.
How to select ACSR cable specifications according to application requirements?
Consider mechanical strength
The ACSR steel core provides mechanical strength for support and resistance to tension. According to the span of the line, wind load, ice load and installation conditions to choose the appropriate proportion of steel core.
Consider electrical requirements
Select the appropriate conductor size according to the line voltage level (e.g. 25kv or 35kV) to ensure voltage regulation and Factor of safety.
Consider environmental factors
In certain specific industrial environments, such as highly contaminated areas, corrosion of ACSR cables is exacerbated. In order to improve the corrosion resistance, all-aluminum alloy conductors (AACSR) are available on the market. AACSR consists of one or more aluminum-magnesium-silicon alloy coils and high strength zinc-coated steel core. In addition, all-aluminum alloy conductors (AAAC and AAC) have better corrosion resistance because they are composed entirely or mainly of aluminum. These types can be considered for use in highly corrosive environments.
Consider International Standards
Ensure cables comply with local, national and international standards such as ASTM B230, B232 and IEC 61089.
Overall, ACSR is still the most widely deployed conductors. They show significant advantages in terms of weight, efficiency and price. If you need latest ACSR conductor price or are unsure of the cable specification you wish to select, please feel free to contact our ZW Cable representatives!
