Statnett is the transmission system operator in Norway, operating over 11.000 km of overhead power lines. Norway is a high latitude country dominated by vast mountain ranges broken up by valleys and fjords. With its high mountains, coastal climate and freezing temperatures, Norway is particularly vulnerable to icing on power lines. In 2020 Statnett installed a Laki Power monitoring station 1.000 meters above sea level on Ålvik mountain to monitor icing on power lines in this remote location. The area is highly exposed to foul weather blowing in off the fjord - creating perfect conditions for ice accumulation on towers, shield wires and phase conductors.
Icing is a major problem for power lines
Ice accretion and associated gallop can put a lot of stress on power lines and towers and results in major repair & maintenance costs.
Currently, Statnett mainly uses two methods to remove ice: 1) by using a helicopter that knocks off the ice with a wooden pole or 2) by heating the power lines with increased current. Heating the power lines is the preferred method since the icing conditions usually entail weather that grounds helicopters and knocking off the ice can damage the wire. However, to use heat or mechanical de-icing approaches on power lines it's important to react quickly when ice starts to accumulate since both methods are best suited if there are small amounts of ice. That’s why an early warning system is key.
To monitor icing conditions at the top of Ålvik mountain Statnett had previously installed a special test span, next to the power line, with weather monitoring devices and other power intensive equipment like cameras. Since tapping into the power line to energize the devices was not possible, Statnett needed to use external power sources like diesel and solar energy.
Ice aggregation on the power line and test span (closer to camera) during the winter.
This set-up had two major drawbacks. Firstly, the external power generation requires expensive equipment and additional maintenance. Secondly, although the test span reflects the condition of the shield wires, used to protect the power lines from lightning strikes, it does not accurately reflect the condition of the power line since there is no current running through the test span.
The Laki Power Solution
The installation costs of the existing monitoring equipment and auxiliary power generation devices amounted to a significant multiple of the price of a Laki Power monitoring station, for this single location, not including yearly maintenance costs due to refueling and other maintenance which could amount to 10-15% of the initial investment annually.
Ålvik Mountain was of course the perfect testing ground since it was in fact the impetus for research projects at Statnett focused on finding solutions that could help in managing the problems associated with power line icing. However, Statnett has multiple locations where icing is an important issue.
So, in August 2020 Óskar Valtýsson, Laki Power’s CTO and founder, and Einar Pétursson, Laki Power’s lead systems developer, boarded a helicopter headed for Ålvik Mountain with the goal of installing an alternative to the current set-up which could provide Statnett with a more reliable and cost-efficient solution to monitor overall icing conditions with the use of cameras and other sensors.
The Laki Power monitoring station captures heavy icing on the conductor.
Approximately 30 minutes after arriving at the power line the station had been successfully installed on the conductor at a fraction of the time and cost involved with setting up the existing monitoring equipment at this remote location.
“Being able to utilize the conductor current to power the monitoring devices is a huge benefit. It reduces costs and provides us with accurate data and a unique viewpoint since the Laki Power station is on the conductor itself”
says Miroslav Radojcic, project manager at Statnett
Event notifications and data analysis
Laki Power provides a user-friendly software solution where users can monitor live data & images and get notifications about events like icing. All data and images are stored in a secure cloud environment for further analysis. On premises solutions will also be available for Laki Power customers.
The Laki Power monitoring station is installed directly on the conductor of the power line with a 4K bidirectional camera and a 6MP fish-eye ground-view camera. This provides Statnett with a viewpoint that is crucial in accurately assessing icing conditions in addition to providing weather data and information about sag of the conductors.
Valuable data and images from the monitoring station is used by Statnett to verify predictive models and icing forecasts. This will enable Statnett to do something about the icing problem before it is too late. “The Laki Power camera view gave us a bird’s eye view of exactly what was happening on the conductor.” says Bjorn Egil Nygaard of Norconsult, Norway’s largest consultancy firm, which works on Statnett’s ICEBOX R&D project.