Extended topological approach for the assessment of structural vulnerability in transmission networks

Power system vulnerability is a key concern in modern societies and many efforts have been devoted to its analysis. Recently, the wide domain of complex networks that can be used to assess the vulnerability of network systems has been applied to power grids as well with focus on the topological vulnerability of the transmission systems based on its structure in terms of the nodes and their connection patterns. However, a pure topological approach, as proposed in the current literature, fails in capturing the specific features of power systems. The authors propose an extended topological approach, which can incorporate several important features of the power grids such as flow paths, line flow limits and gen/load bus distribution. Also, a set of new metrics able to provide an assessment of the system vulnerability is defined. 'Net-ability' measures the aptitude of the grid in transmitting power from generation to load buses efficiently. 'Path redundancy' assesses the available redundancy in terms of paths in transmitting power from a generation to a load bus based on entropy. Based on the previous two metrics, the authors introduce a third metric, the 'survivability', as a global metric to evaluate the aptitude of the network in assuring the possibility to match generation and demand in case of failures or attacks. The metrics proposed will be applied to different test systems and to a real-transmission system to illustrate their application and effectiveness.