Types of Conductor

Definition

The kind of metal known as a conductor enables electrical current to pass through it.Metals like copper, aluminium, and their alloys make up the electrical conductor in the majority of cases. When a potential difference is applied across individual atoms in an electrical conductor, electrical charges are transferred between them. Wire is a form of electrical conductor that is employed. Considerations for the conductor selection can include things like tensile strength, fatigue strength, corona loss, regional conditions, and cost.

Typically, the electrical conductor that is used to transmit power is stranded. When compared to a single wire with a similar cross-sectional area, stranded conductors are much more flexible and strong mechanically. Typically, the centre wire of a stranded conductor is encircled by a series of wire layers made up of 6, 12, 18, 24, etc. wires.

The equivalent copper cross section area, the number of strands, and the average diameter of each strand are used to calculate the conductor’s size. The cross sectional area of a solid conductor of the same length and material as a stranded conductor is its equivalent cross section. A conductor with the same resistance at the same temperature is also included.

Types of Conductor

The three types of conductors that are most frequently used in power systems are hard-drawn copper, hard-drawn aluminium, and steel-cored aluminium. Below is a detailed explanation of some of the most significant conductor types.

Hard Drawn Copper Conductor

High tensile strength is provided by these types of conductors. It has a high scrap value, long life, and electrical conductivity. It works best for distribution tasks involving more spans and tapping.

Cadmium Copper Conductor

By adding 0.7 to 1.0 percent cadmium to copper, its tensile strength is increased by about 50%, but its conductivity is decreased by 15 to 17 percent. The conductor can be built on longer spans with the same sag thanks to its higher tensile strength. So This conductor has the benefits of being simple to join, more resistant to atmospheric conditions, more wear-resistant, simple to machine, etc.

Additionally, the temperature at which copper anneals and softens is raised, and the effects of temperature on stresses are diminished. Sag variation caused by changes in load and temperature is kept to a minimum.

Steel-Cored Copper Conductor (SCC)

One or two layers of copper strands encircle the steel cored copper conductor in this type of conductor. So The conductor gains tensile strength from the steel core.

Copper Welded Conductor

Such conductors are made of steel wires that have uniform copper layers welded onto them. When compared to a solid copper conductor of the same diameter, the conductivity of copper welded conductors varies by 30 to 60%. Such conductor types could be utilised for longer spans, like a river crossing.

Hard-Drawn Aluminium Conductor or All-Aluminum Conductor

Since copper conductors are very expensive, aluminium conductors are used in their place. The aluminium wires are very efficiently handled, transported, and put up. It is used in short, lower voltage transmission lines and distribution lines in urban areas.

Aluminium Conductor Steel Reinforced

The mechanical strength of all aluminium conductors is insufficient for the construction of long span lines. A steel core can be added to the conductor to make up for this strength shortcoming. Aluminium conductor steel reinforced (ACSR) or steel-cored aluminium conductor (SCA) are two names for this type of conductor.

The ACSR conductor has two layers made up of 30 aluminium strands and a central core made of seven steel strands. A 30 Al/7 St conductor stranding is required.The ACSR conductors are used for small sag because of their high tensile strength and light weight.

Smooth Body ACSR Conductor

Another name for this conductor type is Compacted ACSR. The aluminium strands in the traditional ACSR conductor are flattened into segmental shape by being forced through dies. While maintaining the conductor’s electrical and mechanical characteristics, the interstrand space is filled and the diameter of the conductor decreases. This conductor can be produced using various aluminium to steel ratios. The figure below depicts a conductor with a 6 Al/1 St ratio.

Expanded ACSR Conductor

A fibrous or plastic material is inserted between the strands to minimise corona loss and radio interference at high voltage. It is referred to as an expanded conductor because the filling material causes the conductor’s diameter to increase. These conductors are made of paper, which serves as a barrier between the inner steel and aluminium strands.

All Aluminum Alloy Conductor

Urban areas are where such conductors are most frequently used. The conductor’s conductivity and tensile strength work well together. Silmalec is one of the alloys that is used to create such a conductor. This alloy has a 0.5% silicon content, a 0.5% magnesium content, and a remainder of aluminium. Due to their heat treatment, these alloys are very expensive.

ACAR  Conductor

Aluminium Conductor Alloy Reinforced has layers of conductor aluminium surrounding an aluminium alloy core in the centre. So With a strength-weight ratio comparable to ACSR construction with the same diameter, such a conductor provides better conductance.

Alumoweld Conductor

A high strength steel wire is welded with aluminium powder on it. Aluminium covers about 75% of the conductor’s surface area. Compared to core silicon conductor, this is more expensive. SCA conductor cores have been made using it as an earth wire.

Phosphor Bronze Conductor

For extremely long spans, such as river crossings, phosphor bronze is used as a conductor material. Although it has a lower conductivity than copper conductor, it is stronger. For environments with hazardous gases like ammonia, this conductor is superior to the aluminium bronze conductor.

Galvanized Steel Conductor

High tensile strength characterises the galvanised steel conductor. They are utilised in rural settings with small loads over very long distances. So In these situations, the steel conductors might be changed out for a steel core conductor to handle the increased future load. This conductor has a significant voltage drop, inductance, and resistance. But in contrast to other conductors, it has a short life.