  The aim of the present work is to provide the theoretical fundamentals needed
to monitor power grids using high frequency sensors. In our context, network
monitoring refers to the harvesting of different kinds of information: topology
of the grid, load changes, presence of faults and cable degradation. We rely on
transmission line theory to carry out a thorough analysis of how high frequency
signals, such those produced by power line modems, propagate through
multi-conductor power networks. We also consider the presence of electrical
anomalies on the network and analyze how they affect the signal propagation. In
this context, we propose two models that rely on reflectometric and end-to-end
measurements to extrapolate information about possible anomalies. A thorough
discussion is carried out to explain the properties of each model and
measurement method, in order to enable the development of appropriate anomaly
detection and location algorithms.
