Local Electrodynamics of a Disordered Conductor Model System Measured with a Microwave Impedance Microscope

We study the electrodynamic impedance of percolating conductors with a predefined network topology using a scanning microwave impedance microscope at gigahertz frequencies. For a given percolation number we observe strong spatial variations across a sample that correlate with the connected regions (clusters) in the network when the...

Topology-Driven Performance Analysis of Power Grids

Direct connections between nodes usually result in efficient transmission in networks. Such electric power transmission is governed by physical laws, and an assessment purely based on direct connections between nodes and shortest paths may not capture the operation of power grids. Motivated by these facts, in this chapter, we investigate the...

Comparing the Effects of Failures in Power Grids under the AC and DC Power Flow Models

In this paper, we compare the effects of failures in power grids under the nonlinear AC and linearized DC power flow models. First, we numerically demonstrate that when there are no failures and the assumptions underlying the DC model are valid, the DC model approximates the AC model well in four considered test networks. Then, to evaluate...

A Topological Investigation of Power Flow

This paper combines the fundamentals of an electrical grid, such as flow allocation according to Kirchhoff’s laws and the effect of transmission line reactances with spectral graph theory, and expresses the linearized power flow behaviour in slack-bus independent weighted graph matrices to assess the relation between the topological structure...

Nodal vulnerability to targeted attacks in power grids

Due to the open data policies, nowadays, some countries have their power grid data available online. This may bring a new concern to the power grid operators in terms of malicious threats. In this paper, we assess the vulnerability of power grids to targeted attacks based on network science. By employing two graph models for power grids as...

Pseudoinverse of the Laplacian and best spreader node in a network

Determining a set of "important" nodes in a network constitutes a basic endeavor in network science. Inspired by electrical flows in a resistor network, we propose the best conducting node j in a graph G as the minimizer of the diagonal element Qjj† of the pseudoinverse matrix Q† of the weighted Laplacian matrix of the graph G. We propose a...

Analyzing Cascading Failures in Power Grids under the AC and DC Power Flow Models

In this paper, we study cascading failures in power grids under the nonlinear AC and linearized DC power flow models. We numerically compare the evolution of cascades after single line failures under the two flow models in four test networks. The cascade simulations demonstrate that the assumptions underlying the DC model (e.g., ignoring power...