Dr. Martin Wolter, 50Hertz Transmission GmbH
Especially in Germany, the fast increasing amount of energy from renewable energy sources (RESs) combined with slow grid expansions is challenging transmission system operators’ (TSOs’) ability to ensure system security. As a last resort, if all other remedial actions are not sufficient, RES infeed is curtailed. Because most renewable sources are connected to the distribution level, coordinated cooperation between TSOs and DSOs is critical. Furthermore, the TSO needs to know the regionally allocated curtailment potentials. This information is usually not available in sufficiently high resolution, however, requiring TSOs to devise suitable and efficient remedial actions without it.
This session presents the approach of 50Hertz Transmission, one of the four German TSOs. First, sensitivity indices of hand-over points to DSOs on the endangered equipment are calculated, resulting in several regions with almost equal sensitivity values. Thus, by accepting a small loss of efficiency, curtailment does not need to be defined for each busbar, but can be allocated to the specific regions. A second step aims to match the borders of these regions with DSO network groups so that curtailment potentials are easily obtainable. By curtailing only RESs with the highest impact, system security is regained using the least amount of energy and keeping the highest possible amount of RESs online.