High-voltage cables – find manufacturers and suppliers

High-voltage cables are special cables that are used to transport and distribute electrical energy at high voltages (typically over 1,000 volts).

They are used in power transmission and distribution in overhead lines as well as underground and underwater.

Below you will find the main types, important features and characteristics of high-voltage cables and their areas of application, as well as a brief overview of their advantages and disadvantages:

The most important types of high-voltage cables:

1. Oil or oil-impregnated paper cables (oil cables):
   Construction: conductive cores with paper-insulated sheathing, impregnated with insulating oil.
   Advantages: Good electrical insulation properties, long service life.
   Application: Rather older systems or special areas of application.
   Disadvantage: Maintenance-intensive, environmental concerns due to oil.
2. Gas pressure cables (GIL - Gas-Insulated Lines):
   Insulation: Usually filled with nitrogen or SF₆ (sulphur hexafluoride).
   Advantages: Very high voltages possible, high operational safety.
   Application: Power stations, substations, tunnel systems.
   Disadvantage: Expensive, SF₆ is a strong greenhouse gas.
3. XLPE cable (plastic cable with cross-linked polyethylene):
   Insulation: XLPE = cross-linked polyethylene (XLPE - cross-linked polyethylene).
   Advantages: Thermally stable up to approx. 90°C continuous load, no oil or gas filling required, low losses, easy to lay.
   Application: Today the most commonly used cable type in the high-voltage sector.
4. PEX cable (similar to XLPE, different manufacturing process):
   This is also a form of cross-linked polyethylene, but the cross-linking can be done in a different way (e.g. by irradiation).
   Use: Used in similar applications to XLPE cable.
5. Submarine cables:
   Special feature: For underwater installation (e.g. offshore wind farms).
   Can be AC or DC.
   DC submarine cables (HVDC): Particularly more efficient for long distances.
6. High-voltage direct current transmission cables (HVDC cables):
   Insulation: Usually with XLPE or oil insulation.
   Advantages: Lower transmission losses over long distances.
   Use: Intercontinental connections, offshore applications.

Important features and properties of high-voltage cables:

1. High-voltage cables are offered in different voltage classes (e.g. medium voltage, high voltage, extra-high voltage). They must be designed for the specific voltage they are intended to carry. Typical classes are 1 kV to 36 kV (medium voltage), 36 kV to 150 kV (high voltage), and over 150 kV (extra-high voltage).
2. High-voltage cables have special insulation (e.g. made of polyethylene, cross-linked polyethylene (XLPE) or paper oil insulation) that provides dielectric strength and resistance to heat, moisture and chemical influences. The sheath protects the cable from mechanical damage and environmental influences.
3. The conductors in high-voltage cables are made of copper or aluminum. Copper offers higher conductivity, while aluminum is lighter and less expensive. The choice depends on the specific requirements of the application.
4. High-voltage cables are often equipped with shielding to limit electric fields and prevent interference. Proper earthing is important to ensure safety and reduce electrical interference fields.
5. High-voltage cables must be able to withstand high mechanical loads, especially if they are laid underground or undersea. They are often equipped with additional protective layers or steel armoring.
6. The cables must be suitable for the ambient and operating temperatures to which they are exposed. High temperature resistant cables are required for applications in hot climates or near industrial plants.
7. For long transmission distances, high-voltage cables must be as low-loss as possible to maximize energy efficiency and minimize heat generation.

Areas of application for high-voltage cables:

1. Power transmission over long distances:
High-voltage cables are used to transport electrical energy over long distances from the point of generation (e.g. power plants) to distribution stations or large consumption centers. They are crucial for the transmission of electricity from remote energy sources such as wind farms, hydroelectric power plants or solar parks.

2. Energy distribution in urban areas:
In cities and metropolitan areas, high-voltage cables are used to distribute electrical energy within the urban power grid. They connect main distribution stations with local substations and ensure a stable energy supply for large consumers, industrial plants and households.

3. Underground high-voltage transmission:
Underground high-voltage cables are used in densely populated areas where overhead lines are not suitable due to lack of space, aesthetic or safety reasons. They are laid in special protective ducts or conduits to prevent mechanical damage and environmental influences.

4. Submarine high-voltage connections:
High-voltage cables are laid underwater to connect power grids across bodies of water (e.g. seas, lakes or rivers). These so-called submarine cables play an important role in the integration of offshore wind farms and in cross-border electricity trading.

5. Connecting renewable energy sources:
High-voltage cables are essential for connecting offshore and onshore wind farms, solar power plants and other renewable energy sources to the electricity grid. They enable the efficient transmission of generated energy to the nearest substation or directly into the main grid.

6. Special applications in industrial plants:
In certain industrial sectors, such as heavy industry, mining, oil and gas refineries or the chemical industry, high-voltage cables are used to supply large machines and systems with electrical energy.

7. HVDC systems (high voltage direct current transmission):
High-voltage direct current (HVDC) cables are used to transmit large amounts of energy over very long distances and under special conditions (e.g. under water or in difficult terrain). HVDC systems offer lower transmission losses and are ideal for international electricity trading and transfer between non-synchronized grids.

8. bridging and emergency situations:
High-voltage cables can also be used temporarily to bridge outages in the power grid, for example during repairs, maintenance or natural disasters.

Advantages of high-voltage cables:

• They enable the transmission of large amounts of energy over long distances with lower losses.
• High-voltage cables offer a high level of operational safety, are robust and resistant to environmental influences.
• Compared to overhead lines, underground high-voltage cables save space and are more aesthetically pleasing in urban areas.
• They can be used in various environments, including underground, underwater and in extreme climates.

Disadvantages of high voltage cables:

• High-voltage cables and their installation are more expensive than overhead lines, especially when installed underground or undersea.
• Underground and submarine cables are more difficult to maintain and repair, which can increase operating costs.
• Installation can be complex and time-consuming, especially in densely populated or difficult areas.

High-voltage cables are essential for the safe and efficient transmission and distribution of electrical energy, especially over long distances and in special conditions. They play a key role in modern energy infrastructure and are crucial for the operation and integration of renewable energy sources, the networking of power grids and the protection of critical applications and facilities.

Here is an overview of the most important criteria to consider when purchasing high-voltage cables:

When purchasing high voltage cables, it is important to consider several technical and operational factors to ensure that the cables meet the requirements of the specific application.

• Consider the installation environment:
• Underground: Choose cables that are moisture resistant and protected against soil moisture, chemical exposure and rodents.
• Underwater (submarine cables): Look for cables with suitable protection against salt and fresh water, pressure resistance and mechanical stress from waves or currents.
• Overhead lines: Cables for overhead lines must be UV-resistant and weatherproof.
• Pay attention to the voltage class of the cable that is suitable for the application. High-voltage cables are specified in different voltage ranges, e.g. medium voltage (1 kV to 36 kV), high voltage (36 kV to 150 kV) and extra-high voltage (over 150 kV). The cable must be designed for the maximum expected operating voltage.
• Select the correct cable type according to the application:
• Single conductor cables are often suitable for high voltages and high current carrying capacity, while multi-conductor cables are used for specific applications.
• Copper offers high conductivity, but is more expensive and heavier than aluminum. Aluminum is lighter and less expensive, but also less conductive. The choice depends on weight, cost and conductivity requirements.
• Depending on the application, a specific insulation material may be required, e.g. cross-linked polyethylene (XLPE), paper oil or rubber insulation, each of which has different electrical and thermal properties.
• Pay attention to the current carrying capacity of the cable, i.e. the maximum current it can safely carry without overheating. This value depends on the cross-section of the conductor, the material, the insulation and the ambient conditions.
• The insulation must reliably insulate the voltage and ensure operational safety. It should be able to withstand environmental conditions such as moisture, heat, chemical influences and mechanical loads.
• Select a suitable protective sheath for the expected environmental conditions (e.g. UV resistance for outdoor installations, water resistance for underground installation or corrosion protection in maritime environments).
• The cable should have sufficient mechanical strength to withstand mechanical stresses such as tensile forces, vibrations and compression. In demanding installations (e.g. underground or underwater), cables with reinforced sheaths or metal armoring are often required.
• Additional protective devices such as armor or reinforced layers may be required to protect the cable against mechanical damage, rodents or environmental influences.
• Check the temperature resistance of the cable, especially if it is installed in hot environments, near industrial plants or in direct sunlight. Select cables with insulating materials that are designed for the maximum expected operating and ambient temperatures.
• For long transmission distances, cables with a low-loss design are important to minimize transmission losses and heat generation. This helps to increase efficiency and prevents unnecessary energy loss.
• Consider the flexibility and minimum bending radius of the cable, especially if it is used in confined spaces, manhole installations or complicated installations. A suitable bending radius helps to avoid mechanical stresses on the cable insulation and prolongs its service life.
• Ensure that the cable is properly earthed and shielded to meet safety requirements and minimize electrical interference or interference fields. Shielding may consist of metal straps, wires or foil that are grounded to ensure a reliable power line.
• Ensure that the cable complies with the required national and international standards (e.g. IEC, DIN, VDE) and has relevant certifications to ensure safety and quality.
• Check the expected service life and maintenance requirements of the cable. Choose cables that promise a long service life and low maintenance costs, especially in difficult or expensive installation conditions.
• Ask for certificates that confirm the quality and conformity of the cables.
• Consider the cost of the cables, including installation and maintenance costs. The cheapest cables may not be the best if they result in higher operating or maintenance costs. It is important to balance budget against long-term requirements and safety.
• check if there are any special requirements, such as fire resistance, halogen-free or low smoke, if the cable is installed indoors or in safety-critical areas.

Choosing the right high-voltage cable requires a careful analysis of the technical requirements and environmental conditions of the application. By taking these factors into account, you can ensure that the cable will work reliably, efficiently and safely while complying with applicable standards and minimizing long-term costs.

High-voltage cables can be purchased from various suppliers. Comprehensive information about manufacturers and suppliers of High-voltage cables from all over the world can be found on Exportpages.