Supply secured after fire damage in Lienz: APG installs temporary power line

The high-voltage line running through the Drau Valley is a key component of Austria’s transmission grid. Static tests carried out in August 2025 revealed that the damaged pylons were no longer sufficiently stable to withstand the anticipated snow and ice loads of the upcoming winter, posing a risk to operational safety. David Kolm-Schandl of APG explains: "It quickly became clear that immediate action was required. Either refurbishment or a temporary solution had to be completed by the end of the year to guarantee safe operation of the line – a true race against time.”

Complex construction work during ongoing operation

The damaged pylon on the southern connection from the Lienz substation to Soverzene (Italy) was rebuilt on a new, temporary pylon foundation located directly adjacent to one of the affected pylons.

Addressing the damage to the pylon on the Drau Valley line between the Lienz and Obersielach substations near Völkermarkt (Carinthia) required a significantly more complex approach. "It became clear that a temporary line along a modified route was necessary to keep the Drau Valley line in operation,” explains Kolm-Schandl. "Four temporary pylons were erected on concrete ballast foundations, allowing for rapid installation without permanent foundations.” Most of the work was carried out while the line remained in operation. During the relocation of the conductor cables, one system – meaning one side of the line – remained live all the time, with outages limited to only a few hours per day to maintain a secure power supply."

Rapid organization under time pressure

Once the technical solution had been defined, detailed planning for both the line route and the substation area had to be completed under severe time constraints. Agreements with landowners were negotiated, legal requirements fulfilled, and contractors and materials secured – all while contending with ongoing resource and supply chain bottlenecks. 

Construction started in September

Construction of the temporary power line began in September 2025. Four temporary pylon sites were prepared, followed by the erection of the pylons and the installation of approximately 1.2 kilometers of new 220 kV transmission lines. The delivery of the temporary pylons alone was a logistical feat: 70 semi-trailer trucks transported a total of 870 tons of material to Lienz. The pylons were pre-assembled on the ground and then erected using mobile cranes. 

Special challenges:

The project involved a number of particular technical and logistical challenges:

• Crossing the ÖBB railway line: Work above the tracks was only permitted at night within narrowly defined time windows when no train services were operating
• Coordination with intersecting Tinetz linesTemporary installation of a 110 kV overhead line to serve as a construction power line
• Modifications at the Lienz substation: To connect the temporary line to the substation, complex temporary measures had to be implemented on site while the 220 kV system remained in operation.

Gradual commissioning in December

The temporary solution was commissioned in stages. In early December, the first system was switched to the temporary route, followed by the connection of the second system by mid-December. The dismantling of the line sections above the railway line – work that could only be carried out at night – proved to be particularly demanding. 

"The construction of the temporary solution was both technically complex and extremely time-critical.” Emphasizes Kolm-Schandl. “Thanks to the dedication of our teams and the close coordination with all parties involved, we were able to maintain security of supply even under these exceptional circumstances. Operational safety is now fully ensured for the winter period."