Drones will check 7000 km of high voltage cables

In the future, swarms of drones can inspect the 7000 kilometres of high-voltage cables in Denmark, report any errors using artificial intelligence and automatically charge directly on the cables along the way. It will reduce working hours and at the same time reduce costs drastically while increasing security of supply when you get a constant overview of the network.

These are some of the results of the project Drones4Energy, where a team of researchers at SDU in collaboration with national and international partners for three years has developed a drone platform for the inspection of the high-voltage network.

- We have succeeded in achieving the goals we had set ourselves. We have developed a drone platform and an algorithm which ensures that multiple self-flying drones can get very close to the cables, inspect them and along the way charge themselves directly by attaching themselves to the cable, says project manager Emad Samuel Malki Ebeid from the drone centre at Maersk McKinney-Møller Institute at SDU.

Minimises risk and costs

Today, helicopters, man-made drones are used at a distance and employees inspect the wiring with binoculars. Abroad, some crews are even used directly on the cables to inspect the power cables.

By making use of the drone platform developed in Drones4Energy, we can not only minimise the risk to employees and the costs of, for example, very expensive helicopters. But you can also cut down on time and energy consumption drastically, says the drone researcher.

- Today, Energinet's overhead lines are inspected for the most part by helicopter in the first quarter of the year, after which the rest is carried out from the ground, where an employee walks under the lines. The drone platform will be able to spread the inspections over the year. This will mean that all cables are inspected several times a year, so that errors, for example after a storm, are detected more quickly, says the project manager.

8000 crowns per hour

By letting drones perform the task in an autonomous system, according to the research group, you can also reduce costs up to 90 percent and save millions of kroner annually on the total inspection.

According to Energinet, it costs 8000 kroner per hour to send a helicopter into the air. In addition, it can cost up to 100,000 kroner in special places just to inspect one kilometer of cable from a helicopter, says Lars Rasmussen, senior engineer at Energinet.

The project, which is supported with DKK 14 million from the Innovation Fund and totals DKK 19 million, has been extended by six months due to Covid-19.

Therefore, Drones4Energy will not be formally completed until May 2022, but already now the researchers with project manager and associate professor at SDU, Emad Samuel Malki Ebeid, are focusing on the next capital in the project.

- In the next phase, we can see that the cables play a key role to ensure full utilisation of the grid capacity to transfer energy, especially with the growing penetration of electric cars and the expected intensive energy production that will come from the two new artificial energy islands, he says and elaborates:

- Therefore, the cables must be digitised like the rest of the network, and I believe that our developed drone and sensor technologies at SDU can do it on a large scale. Getting it done properly means more energy savings, fewer power outages and ultimately CO2 reductions, and it directly contributes to achieving the green transition goals.

He has worked in Denmark for seven years. For four of those years, he has been employed at SDU's drone centre.

A unique resource

He is pleased that he has succeeded in building a platform that solves the tasks in the original project description and looks forward to the next phase for the energy drones.

- The high-voltage cables make up a unique resource that we largely do not utilise today. By using the cables as a "highway" for drones and letting them work directly on the cables, we can, for example, put sensors and cameras on the wires. From there, we can obtain important knowledge about the landscape around the cables and at the same time ensure that we get a clear and precise status of our extensive energy network, he says.

Trees can be expensive

At Energinet, Lars Rasmussen sees great potential in the constant overview of high-voltage cables in real-time that an army of drones can create. By applying sensors directly to the cables, Energinet can not only get a better overview of the capacity.

- It can be a huge benefit for us that we get drones to help, which can fly autonomously and even charge directly on the cable. The drones help to ensure that we avoid trees and other vegetation growing up in the wires, which is a very big challenge for us today because it is difficult to keep up when we have so many kilometres to keep an eye on, says Lars Rasmussen from Energinet.

In the United States, there are major problems with fallen trees and the weather, which creates extensive power outages in several states. It has major financial and human consequences, as the bill for "blackouts" is as much as 70 billion dollars annually and often results in deaths. President Joe Biden's government has just set aside 65 billion dollars to expand and improve the U.S. supply network, among other things.

Can make better use of the capacity

- Today, we are very careful about sending too much power through, but with the help of the sensors we can get a better overview and constantly follow how the wind and weather affect the cables, which is very important for how we can best utilise the capacity of the cables, says Lars Rasmussen.

Therefore, the drones can help ensure increased use of energy and optimise the maintenance of the energy network to meet the green deal goals in a zero-emission future, assesses the project manager, who already has a name in mind for the next phase of the project.

- I imagine it will be called Drones4Green, he says.

The long-term potential outside Denmark is great, as in the EU alone there is 200,000 km of overhead cables and in the USA, over 250,000 km. The partners behind the research project are in the process of finding funding for the next part of the drone project while looking at possible business opportunities for the technology.