Fingrid introduces Dynamic Line Rating in the transmission grid
In April, Fingrid will introduce Dynamic Line Rating (DLR) on its 400 kV transmission lines to improve the utilisation of the transmission grid. Fingrid is among the first transmission system operators to deploy Dynamic Line Rating at this scale. The technology determines transmission capacity based on actual weather conditions, enabling the existing transmission lines to be used more efficiently.
As part of efforts to improve the efficiency of the transmission grid, Fingrid will roll out Dynamic Line Rating (DLR) nationwide on its 400 kV transmission lines. DLR enables transmission capacities to be determined by taking weather conditions into account. For the first time, dynamic ratings will be used for the main transmission capacity constraints submitted to the day-ahead market on 22 April 2026.
“As society’s electricity consumption and transmission needs increase, it is even more important to make the most efficient use possible of existing transmission connections. By considering up-to-date weather conditions instead of traditional seasonal limits, we can define the efficient use of transmission connections more accurately for prevailing conditions. Dynamic Line Rating also supports the operational reliability of the transmission grid in situations where electricity demand grows and the ways electricity is produced change,” says Mikko Piironen, Head of Operational Planning at Fingrid.
A computational solution supports grid operational planning
The use of Dynamic Line Rating is based on a computational, software-based solution. Forecasts are produced using a machine-learning model based on weather conditions at the time of operation, as well as the characteristics of the transmission line and its surroundings.
The impact of Dynamic Line Rating on transmission capacity varies by season and weather conditions, providing the market with transmission capacity that better reflects reality. In summer, when temperatures are often higher and wind conditions are weaker, transmission capacity is lower than during cooler and windier periods. However, scarcity of transmission capacity has not so far occurred in Finland’s transmission grid during the summer season, and the need for electricity transmission is lower than during colder seasons.
Dynamic Line Rating does not change the technical or equipment-related constraints of the grid. Instead, it provides more accurate and up-to-date information on how close to physical limits transmission lines can be operated safely under prevailing conditions. The method complements Fingrid’s current operational and planning practices.
Fingrid is among the first transmission system operators in the world to introduce computationally determined Dynamic Line Rating at this scale across the entire 400 kV transmission grid. The experience gained will be utilised in Fingrid’s future development work as well as in international cooperation.
Fingrid will monitor the use of Dynamic Line Rating and further develop the operating model as part of the long-term development of the transmission grid. Deployment will be expanded in a controlled manner based on experience and system readiness.
Further information
Mikko Piironen, Head of Unit, Fingrid Oyj, tel. 030 395 4338
Email format: firstname.lastname@fingrid.fi