7,581 research outputs found
Guided Machine Learning for power grid segmentation
The segmentation of large scale power grids into zones is crucial for control
room operators when managing the grid complexity near real time. In this paper
we propose a new method in two steps which is able to automatically do this
segmentation, while taking into account the real time context, in order to help
them handle shifting dynamics. Our method relies on a "guided" machine learning
approach. As a first step, we define and compute a task specific "Influence
Graph" in a guided manner. We indeed simulate on a grid state chosen
interventions, representative of our task of interest (managing active power
flows in our case). For visualization and interpretation, we then build a
higher representation of the grid relevant to this task by applying the graph
community detection algorithm \textit{Infomap} on this Influence Graph. To
illustrate our method and demonstrate its practical interest, we apply it on
commonly used systems, the IEEE-14 and IEEE-118. We show promising and original
interpretable results, especially on the previously well studied RTS-96 system
for grid segmentation. We eventually share initial investigation and results on
a large-scale system, the French power grid, whose segmentation had a
surprising resemblance with RTE's historical partitioning
Giant vacant component left by a random walk in a random d-regular graph
We study the trajectory of a simple random walk on a d-regular graph with d>2
and locally tree-like structure as the number n of vertices grows. Examples of
such graphs include random d-regular graphs and large girth expanders. For
these graphs, we investigate percolative properties of the set of vertices not
visited by the walk until time un, where u>0 is a fixed positive parameter. We
show that this so-called vacant set exhibits a phase transition in u in the
following sense: there exists an explicitly computable threshold u* such that,
with high probability as n grows, if u<u*, then the largest component of the
vacant set has a volume of order n, and if u>u*, then it has a volume of order
log(n). The critical value u* coincides with the critical intensity of a random
interlacement process (introduced by Sznitman [arXiv:0704.2560]) on a d-regular
tree. We also show that the random interlacement model describes the structure
of the vacant set in local neighbourhoods
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