The concept of overhead lines refers to a network of electrical wires that are located above the ground. They are placed on power poles or special towers, and are therefore exposed to difficult and varied weather conditions. Therefore, the wires must meet certain standards for the system to be safe and fulfill its functions. What standards must the wires meet and what types of wires are used in overhead systems?
Check the overhead line cables at the Onninen wholesaler
What standards must overhead line cables meet?
When speaking about standards, three variants should be distinguished - international, European and national regulations. International standards define three categories of cables:
- cables made of aluminum and aluminum alloys IEC 60889;
- steel reinforced aluminium conductors ACSR IEC 61089;
- cables made of aluminum-steel composite (ACSS) - IEC 62219.
In the context of European standards, two standards apply. The first one refers to cables made of aluminium and its alloys (EN 50182), while the second group includes electrical cables made of aluminium, characterised by higher resistance to mechanical damage (EN 50540).
National regulations cover two groups of overhead conductors. The first ones, PN-EN 50182, are made of aluminium and alloys, while the PN-IEC 61089 group specifies standards for steel-reinforced conductors.
To construct overhead power lines, cables with special parameters are used. Due to difficult weather conditions, they must be highly durable. Strong winds and ice deposits on the cables pose a significant threat to their proper operation. The cable system must be highly resistant to corrosion. Overhead power lines are made of materials characterized by high electrical conductivity. This allows for the optimal use of the transmitted energy, reducing losses.
What types of overhead line wires are there?
In practice, overhead line conductors are available in various variants. The basic criterion for classifying different types of conductors is the material from which they are made. The following are used to build overhead lines:
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AAC aluminum wires, they are made exclusively of aluminum, are lightweight and have high electrical conductivity; they are used in low voltage lines, as well as where the weight of the wires used is of great importance; - aluminium wires reinforced with steel (ACSR), have a characteristic structure - there is a steel core inside the wire and an aluminium layer around the core; due to their durability, they are used in medium and high voltage power networks;
- AAAC cables, i.e. those composed of aluminum and aluminum alloys, are used where durability and high corrosion resistance are important;
- ACCC cables - aluminum, reinforced with composite, under the outer layer of aluminum there is a composite core; most often it is made of glass or carbon fiber; this material is used for high voltage lines, especially if they are exposed to difficult conditions;
- AACSR cables, i.e. aluminium-steel cables, aluminium and steel are used to produce them, the core inside is made of steel, they work perfectly in difficult conditions, in high voltage lines, they are resistant to weather conditions, including strong winds;
- ACSS are reinforced aluminum-steel cables, in the central part there is a steel core, and on the outside it is covered with an aluminum layer, these cables are suitable for the construction of high voltage lines, they are characterized by high mechanical strength and thermal expansion;
- HTLS cables - made of high-strength aluminum, they are made exclusively of high-quality aluminum alloys, including composite-reinforced aluminum; they are used in high-voltage systems when it is necessary to limit sags at high loads in emerging overhead systems.
Selecting the right cables is crucial to ensuring that the overhead wire system continues to function for many years.
How does the material of the overhead line conductor affect the installation?
The material from which the overhead line wires are made has a major impact on the proper functioning of the entire installation. The material determines how efficient the system will be, what costs it will generate and at what level energy losses will be observed.
When comparing copper and aluminum, it is worth emphasizing that the former has higher electrical conductivity. In practice, this means that in order to obtain comparable values, the cross-section of the wires in copper installations may be smaller than in the case of aluminum ones.
When compared to corrosion resistance, copper is definitely more resistant. Installations made of aluminum, especially those operating in difficult conditions, must be properly protected.
Also in the context of mechanical strength, copper is a more durable solution. For this reason, copper wires will work better in difficult conditions. They are resistant to damage caused by icing, strong winds. A characteristic feature of copper objects is also a higher resistance to high temperatures than in the case of aluminum.
Despite many undoubted advantages and excellent properties of copper, it is worth knowing that the cost of making an installation using copper wires is significantly higher than in the case of aluminum. To make overhead lines, high-quality solutions should be used, meeting the applicable standards, such as the AsXSn 4x16 cable .
Overhead line cables at the Onninen wholesaler
For safety reasons, insulated wires should be used in overhead lines. Onninen offers high-quality, durable solutions that meet the appropriate standards. Insulated cables are available for sale, such as the AsXSn 2x35 1 kV power cable. This is a two-core cable made of aluminum wires. Its rated power is 1 kV. Polyethylene (PE) material was used to make the insulation. The wire is made of thermally resistant aluminum, ideal for use in difficult conditions, where thermal resistance is one of the key features.