Swissgrid is opting for drone technology to detect damage to extra-high-voltage lines faster and in a more targeted manner. Autonomous drone flights and AI-assisted image analysis make inspections of overhead lines more precise, safer and more sustainable – progress that saves time and money and increases safety.
Regular inspections must be carried out to detect damage to the grid infrastructure at an early stage and rectify it as quickly as possible. This ensures that the transmission system remains available at all times and guarantees security of supply. The use of autonomous drone flights in combination with artificial intelligence opens up new opportunities for more efficient and safer inspections of extra-high-voltage lines and substations.
The Swiss transmission grid is a technical heavyweight: it consists of 6,700 kilometres of lines, 12,000 pylons and 147 switchgears as the basis for ensuring the reliable flow of electricity. However, around two thirds of the grid infrastructure is now between 50 and 80 years old. Age-related wear and tear such as corrosion on steel pylons is not the only problem. Climate change and extreme weather conditions are also having an impact, e.g. heat, storms, lightning, heavy rain, snow and ice – as well as avalanches, debris flows and rockfalls in mountain areas.
Until now, specialists conducted routine inspections from the ground or by climbing pylons. To detect damage to extra-high-voltage lines, for example a material break in an insulator string, specialists also have to access terrain that is sometimes steep and difficult to reach. This is time-consuming and poses safety risks.
As well as performing ground inspections, Swissgrid has been using drones since 2021. Aerial surveys and image analyses are gradually being automated but still involve various manual steps. The process therefore remains labour-intensive, time-consuming and prone to errors when analysing large volumes of data.
The «Maintenance of Infrastructure with Drones in Autonomous Flights» (MIDAS) project is taking the drone-based monitoring of overhead lines and other installations into the digital future. The aim is to digitalise and automate these processes one step at a time. This will make the maintenance of overhead lines and substations more efficient and safer.
Drones carrying high-resolution cameras are used for inspections. Automated flight planning enables the drones to fly over routes autonomously and capture high-resolution inspection images of specific locations and grid elements.
Swissgrid is gradually piloting new technologies and approaches to put them to the test. Every process is validated end-to-end, from the initial potential analysis and regional tests through to operational roll-out. The aim is to replace existing methods with efficient, automated solutions in the medium term and to firmly establish digitalisation in the company in the long term.
Various technologies are incorporated into the project. Together, they form the foundation for automated, digitalised grid inspection.
During the pilot phase, a total of 8,900 pylons and 4,900 km of line routes were inspected from the air. This resulted in 1.5 million images, which were analysed for potential damage or anomalies using AI-assisted image analysis. 1,500 of these images were used for the Smart Image Database to train the AI model to detect anomalies and potential damage to the grid infrastructure.
The project team identified several critical cases, which were then examined in depth by the plant managers at Swissgrid. All the findings are incorporated directly into the «Asset Health Index» – a directory that records the health of Swissgrid’s assets. They therefore form a sound basis for predictive maintenance and the long-term security of the grid. The Smart Image Database plays a crucial role as a data base.
Swissgrid inspected the entire extra-high-voltage grid from the air between 2021 and 2025.
The completed pilot phase forms the basis for a gradual roll-out towards standardised drone deployment for core applications. At the same time, the MIDAS project team is testing additional potential applications. Possibilities include vegetation management along lines or inspections in substations, especially after disturbances or exceptional incidents.
