Identifying vulnerable lines in a power network using complex network theory

The latest developments in complex network theory have provided a new direction to power system research. Based on this theory a power system can be modelled as a graph with nodes and vertices and further analysis can help in identifying the important lines. This paper proposes a new betweenness index using the reactance of the transmission lines as the weight and criteria to measure of vulnerability of a power network. The reactance is a simplified measure of power flow in a lossless transmission line based on the power flow analysis equations. The weighted line index is defined as the reactance of the electric path taken to reach from one node to another node. More power is transmitted along the lines with less reactance, to reach from the source node to destination node, which gives the edges with less reactance a higher weight in the analysis. The analyzes have been carried out on the IEEE 39 bus system and IEEE 118 bus system. The new betweenness index can identify the critical lines of the system, either due to their position in the network or by the power they transmit along the network.