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Abstract

0% of all Renewable Energy Power in Germany is installed in tree-like distribution grids. Intermittent power fluctuations from such sources introduce new dynamics into the lower grid layers. At the same time, distributed resources will have to contribute to stabilize the grid against these fluctuations in the future. In this paper, we model a system of distributed resources as oscillators on a tree-like, lossy power grid and its ability to withstand desynchronization from localized intermittent renewable infeed. We find a remarkable interplay of the network structure and the position of the node at which the fluctuations are fed in. An important precondition for our findings is the presence of losses in distribution grids. Then, the most network central node splits the network into branches with different influence on network stability. Troublemakers, i.e., nodes at which fluctuations are especially exciting the grid, tend to be downstream branches with high net power outflow. For low coupling strength, we also find branches of nodes vulnerable to fluctuations anywhere in the network. These network regions can be predicted at high confidence using an eigenvector based network measure taking the turbulent nature of perturbations into account. While we focus here on tree-like networks, the observed effects also appear, albeit less pronounced, for weakly meshed grids. On the other hand, the observed effects disappear for lossless power grids often studied in the complex system literature. The full decarbonization of the energy sector by 2050 is non-negotiable to meet the emission targets of the Paris agreement.1 Hence, the effort to deploy Renewable Energy Sources (RES) in the electricity, transport, and heat sectors continues and soon, the power system will undergo a regime shift from central conventional to distributed power production. For power grid operators this means: instead of centrally controlling and distributing large amounts of power from few power plants to the lower grid levels, the new challenge is to control lots of small generation units in a swarm-type manner. So far, the influence of the novel dynamics of intermittent power resources in these lower grid levels, called distribution grids, is poorly understood because there was no need to. However, the rapid approach of the regime shift asks for actions. This paper focuses on the stability of synchrony in distribution grids against local intermittent fluctuations at single nodes in the network and identifies network regions that are especially susceptible or infectious towards power fluctuations. Such insights will help to develop control techniques that are both feasible and cost-efficient