Introduction
Faced with continuous growth in energy demand, The acceleration of the modernization of electrical networks becomes a priority. HTLS drivers represent a key solution to increase the capacity of high voltage lines, without modifying existing structures. But how to choose the right type of HTLS driver suitable for your project ? This practical guide helps you understand the different types of HTLS drivers, their advantages, and the technical criteria to take into account to make an informed choice.
What is an HTLS driver ?
HTLS drivers (High Temperature Low Sag, or high temperature, Low arrow) are electric drivers specially designed to transport large amounts of electricity over long distances, while limiting the arrow (cable curvature under the effect of heat and weight). Unlike conventional drivers like ACSR, HTLS drivers can operate at high temperatures (until 210 ° C or even more), without compromising their mechanical performance.
They are made up of advanced materials such as souls in composite fibers, in special steel or thermore -based aluminum alloys, surrounded by conductive layers adapted to extreme thermal constraints. These characteristics allow a much higher current transport capacity, without requiring the modification of existing pylons or structures.
HTLS drivers are now widely used in electrical networks modernization projects, especially in areas with high urban density, Mountain regions, or in saturated energy transport corridors. Their adoption is also encouraged by the energy transition objectives and the rise of intelligent networks.
Why opt for an HTLS driver ?
HTLS drivers have many technical and economic advantages, who make them choice solutions for high -voltage strengthening projects. Here are the main reasons for their growing adoption :
Much superior transport capacity
HTLS drivers use high performance conductive materials, such as low -resistance aluminum alloys or composite souls. So, diameter and equivalent weight, An HTLS driver can transport up to twice as much as a traditional driver. This makes it possible to considerably increase the capacity of existing lines, without modifying the infrastructure in place.
Reduction of high temperature thermal arrow
Unlike traditional drivers, HTLS drivers can operate at high temperatures, going up to 210 ° C, even more. Even under these extreme conditions, their deformation remains minimal. This is explained by the use of materials with low thermal expansion coefficient, such as composite souls or special steels. This characteristic is essential to guarantee security in forced environments, like dense urban areas or road crosses.
Economical solution to modernize without rebuilding
Replacing an old driver with HTLS makes it possible to double the capacity of a line, without replacing pylons or modifying the spacing of structures. This greatly reduces civil engineering costs, implementation deadlines, and service interruptions.
Increased resistance to extreme environments
HTLS drivers better support severe conditions such as strong winds, Extreme thermal cycles, humidity or pollution. They are therefore suitable for regions exposed to difficult climatic conditions.
ZMS Cable offers several types of HTLS conductors capable of operating in extreme environments, with a personalization service according to the technical constraints of the project.
Main types of HTLS drivers and their characteristics
There are several types of HTLS drivers, each designed to meet specific temperature constraints, mechanical or environmental resistance. Here are the most commonly used models in high voltage lines.
ACCC drivers (Aluminium Conductor Composite Core)
ACCC drivers consist of a central soul in composite material (generally in carbon and glass fibers), Surrounded by thermoreisting aluminum wires.
This composite nucleus has almost zero thermal dilation, which strongly limits the arrow, Even at very high temperature.
Thanks to their excellent weight/resistance ratio, ACCC drivers can transport a large amount of current while maintaining a low level of arrow. They are therefore particularly suitable for long worn lines, to urban areas, and rehabilitation projects without modification of pylons.
Other advantage : The composite soul of ACCC drivers is lighter. The result is a lower voltage/load on the support structures of the lines such as the pylons, Insulates, transverse arms, etc. This allows easy installation without the need for structural strengthening.
ACSS drivers (Aluminium Conductor Steel Supported)
ACSS drivers are made up of one or more galvanized steel threads in the center, Surrounded by recuite aluminum threads. This type of construction offers excellent mechanical resistance and allows high temperature operation, up to 250 ° C.
Unlike conventional drivers, ACSS reception aluminum is not pre-set. This means that most of the traction is supported by the steel soul, even hot. This behavior makes ACSS particularly suitable for long litters or lines subject to significant mechanical loads, as in winding or mountainous regions.
Moreover, their high thermal performance makes it possible to strengthen an existing line without changing the structures, while guaranteeing great long -term reliability.
ACCR drivers (Aluminium Conductor Composite Reinforced)
ACCR drivers use a central soul in reinforced aluminum alloy, often combined with ceramic fibers or other advanced materials.
This structure gives them excellent mechanical resistance, while maintaining lightness greater than that of steel soul drivers.
The main advantage of ACCR lies in their very low thermal dilation combined with high electrical conductivity. They can operate at temperatures up to 210 ° C, tout en limitant la flèche thermique. Cela en fait une solution idéale pour les zones contraintes par le gabarit, comme les traversées de fleuves, les corridors urbains denses ou les lignes à fort encombrement visuel.
What's more, their resistance to corrosion is excellent, ce qui en fait un bon choix pour les environnements côtiers ou industriels agressifs.
Invar drivers / Gap-Type
Les conducteurs Invar, également appelés conducteurs de type Gap, sont constitués d’un cœur en alliage Invar (fer-nickel à très faible coefficient de dilatation) entouré de fils en aluminium classique. Ce type de conducteur présente une très bonne stabilité dimensionnelle à haute température, up to 250 ° C.
La particularité du conducteur Gap réside dans la présence d’un espace (“gap”) entre l’âme et la couche d’aluminium, filled with fat or slippery.
This configuration allows dilating aluminum independently of the nucleus, which effectively limits the thermal arrow. So, The driver remains efficient even during extreme temperature variations.
Invar drivers are often used in long -range line renovation projects, or when the mechanical constraints are high but the vertical size must remain minimal.
TACSR drivers / Educate (Trapezoidal Aluminum Conductor Steel Reinforced / Aluminum Conductor Steel Reinforced Aluminum)
TACSR and TACSRA drivers are advanced variants of conventional ACSR conductors.
They integrate a reinforced steel heart to ensure high mechanical resistance, surrounded by aluminum threads arranged in trapezoidal shape (Proficiency) or classic (Educate).
This design improves conductive material density, allowing better conductivity and increased transport capacity compared to traditional ACSR.
They also support higher operating temperatures, usually up to 150-170 ° C.
THE TACSR drivers / Educate are often used for high voltage lines requiring a good compromise between mechanical performance and thermal capacity, especially in regions under variable climatic conditions.
Criteria to take into account to choose a HTLS driver
The choice of an HTLS driver is not only based on his nominal performance. It must be adapted to the specific constraints of the project and the operating objectives. Here are the main criteria to consider :
Required operating temperature
Each type of HTLS driver has a specific thermal limit (generally between 150 ° C and 250 ° C). It is essential to choose a model capable of operating at the maximum temperature provided without loss of performance or excessive extension.
Mechanical line constraint
Some lines require high resistance to traction (mountainous areas, long, Extreme climatic conditions). Steel or invar soul drivers will be more suitable in this case.
Reduction of the thermal arrow
In urban environments, Road or railway crossings, It is crucial to minimize the arrow. Low thermal dilation drivers (ACCC, ACCR, Invar) are to be preferred.
Compatibility with existing structures
If the project concerns the renovation of an existing line, It is necessary to take into account the maximum mechanical loads that the pylons can support. Lighter drivers or reduced efforts on structures (Like ACCCs) can avoid expensive reinforcement work.
Environmental conditions
Salt environment, Corrosive industrial zones, strong thermal amplitudes ... so many factors that influence the choice of the material of the soul and the strands. For example, ACCR drivers are renowned for their excellent corrosion resistance.
Local standards and requirements
The chosen driver must comply with international standards (IEC, ASTM, etc.) but also local technical specificities (frequency, tension nominale, type de fixation, etc.).
Comparison of HTLS drivers according to international standards
To facilitate the choice of a HTLS driver adapted to a given project, It is useful to compare their technical performance on the basis of the most common international standards (IEC, ASTM, etc.).
The following table has a synthetic comparison of the main types of HTLS conductors :
| Driver type | Max temperature. (°C) | Thermal arrow | Mechanical resistance | Conductivity | Relative weight | Current standards |
|---|---|---|---|---|---|---|
| ACCC | 200–210 | Very weak | Average | High | Light | ASTM B987, IEC 62004 |
| ACSS | Until 250 | Average | High | Average | Pupil | ASTM B856 |
| ACCR | Until 210 | Very weak | Average to high | High | Light | ASTM B609 |
| Invar / Gap | Until 250 | Weak | Very high | Average | AVERAGE | IEC 61089 + Specific specs |
| Proficiency / Educate | 150–170 | Average | High | Average | Pupil | IEC 62004, IS 398 |
Interpretation of criteria
Maximum service temperature : Crucial for overload projects or in areas with high energy demand.
Thermal arrow : The more it is weak, The more the driver is suitable for urban areas, to critical air passages, etc.
Mechanical resistance : Determines the conductor's ability to support the tension between pylons, especially in windy or mountainous areas.
Standards : It is essential to ensure that drivers are certified according to recognized standards (ASTM, IEC), guarantee of quality and technical compatibility.
ZMS Cable offers HTLS drivers in accordance with international standards and can provide corresponding testing and test certificates on request on request.
Case study : HTLS driver selection scenario
To illustrate the selection process of an adapted HTLS driver, Take a concrete example of modernization of an existing line.
Project context
An electricity company currently plans to strengthen a line existing 220KV. This line crosses a peri -urban area with high construction density. However, Support structures (pylons, insulators) cannot be replaced. It is therefore necessary to increase the capacity of the line without modifying the existing infrastructure.
Technical constraints identified
- Increase current transport capacity by at least 80 %
- Minimize the thermal arrow (line above roads and dwellings)
- Maintain or lighten the mechanical load on existing pylons
- Ensure excellent corrosion resistance (Semi-industrial area)
- Respect IEC standards and limit intervention costs
Analysis and selection
- Classic ACSR : unsuitable, Insufficient capacity and thermal resistance
- ACCC : composite soul, reduced weight, Excellent conductivity, low thermal arrow
- ACCR : Good thermal and mechanical performance, But higher cost
- ACSS : higher eligible temperature, But significant weight and average arrow
- Proficiency : possible improvement, But less efficient on the thermal arrow
- Invar / Gap : too rigid for short and more expensive spans for installation
Conclusion
The ACCC driver is here the optimal choice :
- Increase in capacity without overload of structures
- Very low thermal arrow, Compatible with urban environment
- Good performance report / cost
- Certification according to ASTM and IEC standards
ZMS Cable has already supported similar projects with Personalized ACCI solutions, including the load study, the supply of cables and technical assistance to installation.
If you need more detailed information, do not hesitate to contact us !
Conclusion
HTLS drivers offer a concrete response to the challenges of strengthening power lines without modifying existing structures. Thanks to their thermal performance, mechanical and environmental, They allow rapid and effective modernization of networks. A judicious choice, associated with rigorous tests and careful implementation, is essential to guarantee their full efficiency. With the development of renewable energies and the increase in electric flows, HTLS drivers will play an increasingly central role in the transport networks of the future.