Analysis And Evaluation Of Ningxia Power Grid Vulnerabilit

With the unceasing development of the global economy, large-scaled cross-region and correlated power grids make the whole power system become more and more complex. This could improve the efficiency of system but increase the complexity of power grid at the same time. Some blackouts occurred frequently in recent years indicate that local breakdowns would spread quickly, lead a series of power outage even knock out power systems. It is necessary to use global method of complex network theory to study the causes of cascading failures in power grids and to reveal the inherent mechanism of fault propagation.The aim of this paper is to establish a complex network model of the Ningxia power grid, based on the theory of complex network. Node degree, degree distribution, the shortest distance, clustering coefficient,n ode betweenness and edges betweenness of the network are obtained by using of Pajek. The type of Ningxia power grid is determined throug analyzing the degree distribution and clustering coefficient. The fault simulations are modeled, one is randomly removing line/point, and the other is purposefully removing line/point. The vulnerability of Ningxia power grid under different attack styles is analyzed by comparing the varies characteristic parameters and two fault indexes after attacks. The fault simulations of IEEE 118 node test systems are modeled too, the comparisons between the IEEE test systems and Ningxia power grid after attacks are carried out, and the difference between the two grids is analyzed.The weighted power grid model is built based on complex network theory by choosing impedance of transmission lines as the weighted parameters, and then the structural vulnerability assessment method for power grid is presented, and the calculation method of betweenness and the shortest distance in weighted power grids is proposed which are applied to determine the important nodes and lines of Ningxia power grid.