AUTHOR=Afonin Andrei , Chertkov Michael TITLE=Which Neural Network to Choose for Post-Fault Localization, Dynamic State Estimation, and Optimal Measurement Placement in Power Systems? JOURNAL=Frontiers in Big Data VOLUME=Volume 4 - 2021 YEAR=2021 URL=https://www.frontiersin.org/journals/big-data/articles/10.3389/fdata.2021.692493 DOI=10.3389/fdata.2021.692493 ISSN=2624-909X ABSTRACT=We consider a power transmission system monitored with Phasor Measurement Units (PMUs) placed at significant, but not all, nodes of the system. Assuming that a sufficient number of distinct single-line faults, specifically pre-fault state and (not cleared) post-fault state, are recorded by the PMUs and are available for training, we, first, design a comprehensive sequence of Neural Networks (NNs) locating the faulty line. Performance of different NNs in the sequence, including Linear Regression, Feed-Forward NN, AlexNet, Graph Convolutional NN, Neural Linear Ordinary Differential Equations (ODE) and Neural Graph-based ODE, ordered according to the type and amount of the power flow physics involved, are compared for different levels of observability. Second, we build a sequence of advanced Power-System-Dynamics-Informed and Neural-ODE based Machine Learning schemes trained, given pre-fault state, to predict the post-fault state and also, in parallel, to estimate system parameters. Finally, third, and continuing to work with the first (fault localization) setting we design a (NN-based) algorithm which discovers optimal PMU placement.