2026-03-19
Litgrid implements a proven innovation – Dynamic Line Rating technology to increase electricity transmission capacity
Lithuanian electricity transmission system operator Litgrid has signed a contract for the procurement of Dynamic Line Rating (DLR) technology. The system, which measures and forecasts overhead line parameters, will enable greater volumes of electricity to be transmitted across existing lines. This will allow the transmission network to carry more electricity generated from renewable energy sources.
"Dynamic Line Rating technology, under suitable environmental conditions, makes it possible to significantly increase line capacity at considerably lower cost than full line reconstruction, allowing more electricity to flow through them. Greater overhead line capacity will enable renewable energy power plants to generate more electricity without restrictions. We are pleased that, in reaching our investment decision, we were able to draw on the results of completed pilot trials," said Donatas Matelionis, Head of Litgrid's Head of Power System Operations department.
The DLR implementation contract was signed with the supplier group that won the international public procurement – comprising Portuguese company GML Transmission Line Solutions S.A. and Spanish company Energiot Devices S.L. – and is valued at €341,000.
The contract covers the installation of the Dynamic Line Rating system, software licensing, the supply of physical sensors, and ongoing system maintenance and support. The DLR system is expected to become operational in early 2027.
The results of two previously conducted pilot projects for this technology indicate that, using Dynamic Line Rating, the transmission capacity of electricity lines increased by an average of 52 per cent compared with the established design capacity.
At present, static line rating is used for electricity transmission system management – this is determined during line design and varies within a narrow range depending on air temperature. The actual capacity of overhead lines depends not only on air temperature but also on other factors, such as wind speed and direction, solar irradiance, and precipitation. The new system takes account of many of these variables and forecasts future line capacity.
The system will be deployed on lines equipped with both physical and virtual sensors. On 25 lines totalling 844 kilometres in length, a system using virtual sensors will be installed. These will calculate the capacity potential of electricity overhead lines based on technical data for transmission lines provided by Litgrid specialists, tower coordinates, and data supplied by weather forecast providers.
On 13 lines spanning 328 kilometres, physical sensors will be installed to measure weather conditions and line parameters, whilst software operating on a mathematical model will monitor and forecast available line capacity.
Dynamic Line Rating technology is being deployed on lines where significant renewable energy generation is already installed or planned, with the aim of making maximum use of the transmission network for conveying wind and solar electricity.
The combined installed capacity of solar and wind power plants already operating in Lithuania, across both transmission and distribution networks, stands at 5,978 MW, whilst the permitted generation capacity reaches 5.2 GW – accounting for more than 60 per cent of the country's total electricity generation capability.
