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The transition to sustainable and environmentally friendly energy supply is a challenge for both society and industry.
The power grid is becoming a bottleneck. However, expanding the grid is time-consuming and costly. But actually, it is already possible to improve the utilization of existing capacities – by means of the weather-dependent overhead line operation, for short: dynamic line rating (DLR).

Conductors are expanding with increasing temperature, the lines are sagging, the sag being influenced by both, the current load fed into the grid and the microclimate around the lines. In favorable weather conditions, the conductors can withstand an increase in current load of up to 150 percent. This requires smart and reliable monitoring of the microclimate around the lines.

Smart dynamic line rating
enables an increase of the
fed-in current load up to


Midsummer weather all year long?
Use unused capacities of the lines!

In order to guarantee safe operation even under extreme conditions, German grid operators calculated with the so-called normative midsummer weather conditions for a long time; i.e. with a static ambient
temperature of 35 °C (95 °F), weak wind with a speed of 0.6 m/s and strong solar radiation of 900 W/m².

In Central Europe, such conditions only prevail on a few days of the year; on all other days, the lines can, therefore, tolerate a greater current load. The objective of dynamic line rating is to use these previously unused capacities, adjust them to the actual conductor temperature and avoid expensive temporary shutdowns (redispatches).

Pilot project for indirect measurement of conductor temperature


A practical and reliable method for indirect measurement of the conductor temperature


  • Weather sensor Lufft WS501, which measures
    temperature, solar radiation and wind speed, and direction
  • mounted on the mast measure the conditions prevailing on the conductor lines as precisely as possible
  • Sutron XLink 500 data logger for reliable data collection and storages storages
  • Power supply and communication are provided by a specially designed OTT MetSystems cabinet, powered by a solar panel


since the start of the test phase in July 2019, all components function reliably and have been transmitting data on the microclimate around the power lines without interruption. The information collected also makes it possible to forecast icing of the conductor cables. This helps the network operators to take appropriate measures on time.

"Testing our solution for dynamic line rating in a pilot project is exciting and informative. We are proud that all the equipment works in this open space with strong electromagnetic fields and has been recording and transmitting data without interruption since July 2019."

Udo Kronmüller – Senior Sales Manager, OTT HydroMet

Dynamic line rating in practice - The complete solution from one source

Lufft WS501-UMB

Compact all-in-one-weather sensor for measuring air
temperature, relative humidity, air pressure, wind direction, wind speed, and radiation.

SUTRON XLink 500

Multi-sensor datalogger/transmitter with transmission via IRIDIUM or cellular. Ideal for use with multiple digital and analog sensors supporting advanced monitoring applications.

OTT Switch cabinet and telemetry

Turnkey control cabinet that can be flexibly equipped, with a clear price advantage over individual solutions.

Do you want to learn more?

Contact us now!

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Source: Tennet,
Freileitungsmonitoring, August 2018

Meteorology Division of