Power Grids Vulnerability Analysis Based On Complex Network

Power grids are one kind of the largest man-made networks in the world. The research of the power grids are based on the reduction theory in the past, but this method has not suitable for the analysis of the power grid. Analysis of the power grids based on complex networks theory is more effective on account of the complexity of the topology and characteristics of the power grids. Meanwhile, there are many differences between complex networks and power grids. Energy is transmitted though the shortest path between two nodes in complex networks. However, electric power is transmitted though all of the path between two nodes in power grids; Characteristics of lines and nodes are idealized in complex networks. In power grids, the transmission capacity of lines and nodes are considered.The indicators of the assess the vulnerability of lines in power grids was degree and betweenness ever before. In this paper, we introduce a new index called the electrical degree-betweenness index to assess the vulnerability of lines in power grids. The electrical degree-betweenness index based on electrical characteristicscombines effectively the degree and the betweenness of lines. This article reveals the effectively the vulnerability of lines.In the current research, the assess of the vulnerability indicators of nodes in power grids is simply degree, betweenness and k-shell. In this paper we further develop this concept and propose a new index called the triple electrical index. The index based on the electrical characteristics is a combination of three kinds of indicators by Euler distance formula. Above index has electrical characteristics, and from three aspects to synthetically evaluate the vulnerability of the nodes.The identification method to prevent the key nodes and lines of the power grids breakdown was studied. In the IEEE-118 bus system fault simulation using static analysis and dynamic analysis, with the largest connected cluster and global function to measure the vulnerability of the power grid. The fault simulation results shown that power grids are robust against random attacks, but power grids will suffer significantly if particular nodes and lines are attacked continuously. Especially, the attck of the nodes with high triple electrical index and lines with high electrical degree-betweenness index are more likely to occur power grids failure. It can effectively prevent the expansion of power grid cascading breakdown by protecting those key nodes and lines.