Transmission line monitoring for TransnetBW

The expansion of renewable energies presents the transmission grid with new challenges due to increased load. Here, the transmission power of an overhead line is largely restricted by its operating temperature. Therefore any wearing of the line as well as strong sagging from heat transfer is to be avoided. However, the standards for maximal current carrying capacity do not take into account that transmission lines experience cooling from external influences such as outside temperature or wind.

In order to effectively send more electricity through power lines and save costs for the grid expansion in the process, transmission line monitoring is a cost-efficient and fast alternative. As a prerequisite to this, energy & meteo systems analyzed the current carrying capacity for the transmission grid operator TransnetBW. In order to monitor the calculated weak points, additional positioning of the respective meteorological measurement stations were calculated allowing for the prognostic calculation of the current carrying capacity in an operational state.

Hot spot analysis

A pre-analysis from historical data was ascertained to show how much load the power grid could handle. On the basis of this evaluation, the maximum current carrying capacity was calculated from power line characteristics and historical meteorological data. For each power circuit, sections with the historically lowest capacity were determined, so-called hot spots, for which power lines may be exposed to, for example, a particularly strong cooling from wind.

Set up of measurement stations

Based on the evaluation results of the hot spot analysis, site recommendations were drawn up for weather stations in the entire grid region. The measurement stations are able to map the meteorological conditions at the hot spots in order to predictively determine the load capacity of the lines. Hot spots with similar meteorological conditions could thus be covered by fewer measurement
stations, keeping the number of stations to be set up small and effectively saving costs.

Advantages of power line monitoring

Power line monitoring can significantly increase the transmission capacity of the grid. The economic advantages of increased current carrying capacity are manifested through the saving of new lines and the associated costs. The prognostic nature of the determination of load capacity allows grid operators to achieve a better grid planning, preventing grid bottlenecks, for example, and the associated input management.