Graph neural networks for power grid operational risk assessment under evolving grid topology
This work addresses operational risk assessment for power grid operators, offering a faster alternative to traditional methods, though it is incremental as it applies existing GNN techniques to a specific domain problem.
The paper tackles the problem of predicting risky conditions in power grids hours ahead without detailed future topology information, using graph neural networks (GNNs) trained on data from mixed-integer linear programming solutions. The results show that GNNs provide fast and accurate predictions, acting as efficient proxies for computationally expensive algorithms, with demonstrated accuracy on synthetic grids up to 2848 buses.
This article investigates the ability of graph neural networks (GNNs) to identify risky conditions in a power grid over the subsequent few hours, without explicit, high-resolution information regarding future generator on/off status (grid topology) or power dispatch decisions. The GNNs are trained using supervised learning, to predict the power grid's aggregated bus-level (either zonal or system-level) or individual branch-level state under different power supply and demand conditions. The variability of the stochastic grid variables (wind/solar generation and load demand), and their statistical correlations, are rigorously considered while generating the inputs for the training data. The outputs in the training data, obtained by solving numerous mixed-integer linear programming (MILP) optimal power flow problems, correspond to system-level, zonal and transmission line-level quantities of interest (QoIs). The QoIs predicted by the GNNs are used to conduct hours-ahead, sampling-based reliability and risk assessment w.r.t. zonal and system-level (load shedding) as well as branch-level (overloading) failure events. The proposed methodology is demonstrated for three synthetic grids with sizes ranging from 118 to 2848 buses. Our results demonstrate that GNNs are capable of providing fast and accurate prediction of QoIs and can be good proxies for computationally expensive MILP algorithms. The excellent accuracy of GNN-based reliability and risk assessment suggests that GNN models can substantially improve situational awareness by quickly providing rigorous reliability and risk estimates.