Grid expansion: Renewable energy on “old” power lines

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The energy transformation in Germany urgently needs new power lines to transport wind power generated along the northern coast to the country’s industrial centers in the south. Until these new lines are in place, digital technologies are to be used to “squeeze” capacity reserves into the existing grid.

Volatile renewable energies, combined with the growing international trading with electricity, are pushing the power distribution grid to its limits. The grid infrastructure must be significantly expanded to ensure that power can continue to be reliably supplied at acceptable rates. Unfortunately, this expansion involves drawn-out approval processes and high costs.

The need to string or lay new power lines could be significantly reduced by improving the use of existing overhead lines. Such steps could include using weather conditions as the foundation of short-range forecasts about current carrying capacity. The maximum current of the conductor line could be increased depending on the ambient temperature, solar radiation, wind speed and wind direction. And it could be done without exceeding the maximum permissible conductor temperature and while maintaining the minimum distance of the conductor to the ground or objects. A key role in this process is played by the cooling wind, which is influenced by the local topography and vegetation.

Grid expansion with sensor networks

To “pep up” the existing infrastructure, researchers and industry partners in a project called “PrognoNetz” are developing national grids equipped with smart sensors. Unlike conventional weather stations, a concentrated set of sensors is placed near overhead power lines to measure weather conditions as precisely as possible.

To do this job, the wireless sensor networks must be able to withstand tough environmental conditions. With the help of the data they have collected, the self-learning algorithms automatically generate forecasts about current carrying capacity for periods that range from hours to even days. Historic weather data and topographical features are used to create intelligent models for every line in the power grid.

As part of the PrognoNetz project, scientists at the KIT (Karlsruhe Institute of Technology) are working on a range of things. These include forecast models based on artificial intelligence, a more precise, laser-based wind sensor and unmanned drones that can be used to install and maintain the weather sensors on the power lines. The self-learning, meteorological network is being designed for initial use on current high-voltage power lines and by TransnetBW, the operator of the electricity transmission grid in the German state of Baden-Württemberg.

With the help of grids based on artificial intelligence, existing power grids can be optimally used at all times by adjusting operations to weather conditions and bottlenecks can be avoided. As a result of such steps, power transmission can be boosted by 15 percent to 30 percent during periods of favorable conditions, which include low outside temperatures and strong wind.




Grid expansion (Image: pixabay).

Electricity produced by wind power systems in northern Germany travels all the way to the foothills of the Alps through new and old power lines. (Image: pixabay).