Holzheim Substation

The Holzheim substation has been connected to the high-voltage grid since October 16, 2025.

The project presented some unique challenges, which our team was able to overcome thanks to years of experience and technical precision.

The confined construction site, located in the immediate vicinity of an existing substation operated by the utility company, left little room for traditional construction site facilities. Nevertheless, the work was carried out efficiently and safely.

Another important aspect was the preparation of the subgrade. By carefully treating the existing material and using special additives, it was possible to avoid completely replacing the subgrade. This not only sped up construction but also conserved resources.

Since the terrain was too steep to allow for a natural slope, the client had to secure the access road with retaining walls on both sides. However, these could not be erected until after the large-scale shipments had been delivered, as they also serve as flood protection on the downhill side for the existing substation located upstream.

To protect the facility from water intrusion, the substation was elevated above the natural slope. This allows rainwater and surface water to drain away from the structure in a controlled manner during heavy rainfall events. In total, the site had to be leveled by approximately 3.5 meters.

During the construction phase, the portal also had to be redesigned to use a harp-style tensioning system. In this system, the guide cables are not tensioned in parallel but in a fan-shaped pattern, similar to the strings of a harp. This design allows for a stable and space-saving connection of the cables and adapts optimally to the local conditions.

Projects like the one in Holzheim show that we address site-specific challenges with creative solutions. Throughout the project, careful planning and technical adjustments always go hand in hand.