ENTSO-ENew Tower Concepts
Overview
The main components of overhead lines (OHLs) are towers, tower foundation, conductors, and insulators. The task of the tower is to carry the conductors. In high voltage (HV) and extra-high voltage (EHV) applications, mainly lattice towers are used due to their high efficiency, security in operation, and cost-effectiveness.
While conventional lattice tower concepts are understood by the public as outdated, new tower concepts have been introduced to show the possible alternatives and possibly solve the acceptance issue.
The primary OHL technology characteristics are as follows:
- Tower body (lattice towers, full-wall pylon (concrete, steel, composite))
- Cross arm type (lattice, full-wall, insulated)
- Number of earthing wires (one or two)
- Number of circuits (one to six)
- Arrangement of circuit phases (delta, one horizontal plane, one vertical plane)
Benefits
The target of new tower concepts is to create a compact, environment friendly and affordable tower design that potentially increases public acceptance. At present, conventional lattice towers are most efficient considering economic, sustainability and practical aspects.
Current Enablers
Every tower design has its advantages and disadvantages. Typically, optimising one value (e.g. magnetic field) worsens another value (e.g. noise emission, or electric field). Some towers have disadvantages in maintenance and repair (climbing is restricted, accessibility needs to be solved by other means). Another important factor in new tower designs is the foundation, which is not seen and can be very difficult to realise. Moreover, there is little experience and few existing standards for new tower concepts. Hence, it can be expected that their lifetime will be shorter than conventional lattice towers.
R&D Needs
Several R&D activities listed below can contribute to further improving the technology:
- Pilot projects are primarily needed to demonstrate the feasibility of the new tower designs. Moreover, it is easier to answer the public acceptance questions if the designs can be seen in a real environment.
- Every new design requires numerous studies.
- The evaluation of the service experience and measurement of the acceptance level after introducing new types across all different solutions holds interest.
- Methodologies and comparisons of different tower designs from the sustainability and resilience perspective should be developed.
The technology is in line with milestone “Circular economy and environmentally friendly components included in planning and asset management” under Mission 1 of the ENTSO-E RDI Roadmap 2024-2034.
TSO Applications
Examples
| Location: Denmark [1] | Year: 2019 |
|---|---|
| Description: The European Composite Pylon (ECP) project looks to offer compact, easier-to-erect pylons that support the energy transition in an aesthetically pleasing way. | |
| Design: A full-wall composite tower with two full-wall composite hollow insulators with silicon housing cross-arms arranged in a “Y” shape, carrying two 380 kV circuits arranged in an inclined plane. | |
| Results: Three power poles were erected in one day in Denmark in 2021, half as tall as conventional towers. Faster installation and easier maintenance. | |
| Location: Germany/Netherlands [2] | Year: 2018 |
|---|---|
| Description: Ten-year-long project to increase transmission capacity via 380 kV lines across Germany and the Netherlands using a new tower structure that has a minimum visual impact. | |
| Design: A full-wall steel tower with two full-wall cross-arms arranged on two levels carrying two 380 kV circuits arranged in delta (Amprion). | |
| Results: Increased transmission capacity between Germany and the Netherlands. 7 km section erected between Millingen substation and the Dutch border. Visually aesthetic structures. | |
| Location: Randstad, Netherlands [3] | Year: 2016 |
|---|---|
| Description: Two full-wall steel towers with insulated cross-arms carrying one 380 kV circuit per tower. Circuits are arranged in a way that allows reducing the magnetic field below the line (TenneT). | |
| Design: Tapered papyrus-white masts in pairs that carry the cables with short arms and so-called suspenders in between and close together. | |
| Results: Minimum protruding elements, less space-consuming, and a narrower magnetic field generated, while maintaining a minimum visual impact. | |
| Location: Saxony-Anhalt, Germany [4] | Year: 2013 |
|---|---|
| Description: A research and innovation project carried out at 50 Hz for an Alternating Current (AC) OHL called CompactLine. Research spanning from 2013 to 2017, with testing carried out in 2018–2019. | |
| Design: A full-wall steel tower with two full-wall cross-arms arranged in one plane carrying two 380 kV circuits arranged in the horizontal plane. The aluminium conductors are carried on the steel conductor located above. | |
| Results: 2 km stretch of CompactLine established in Saxony-Anhalt. The towers are significantly shorter and less wide than conventional towers, reducing visual impact on the landscape. | |
Technology Readiness Level The TRL has been assigned to reflect the European state of the art for TSOs, following the guidelines available here.
- TRL 9 for the lattice towers in general.
- TRL 7 for already-built full-wall towers.
- TRL 7 for lattice tower with insulated cross-arms.
- TRL 6 or lower for all other designs.
References and further reading
Reinhausen, “A new design for power poles”.
ZJA, “Wintrack pylons”.
50 Hertz, “compactLine”.