Using Disturbance Data to Assess Vulnerability of Electric Power Delivery Systems

In this paper we discuss how to assess the vulnerability of electric power delivery systems with the help of standard power system performance indices. In two case studies, statistical analyses of disturbance data from Swedish power transmission and distribution are presented and discussed. The following indicators are used in the case studies: unserved energy, power loss, restoration time, and the number of disturbances with power loss. We demonstrate that disturbance size Q for larger values of indices shows a power-law distribution, i.e., P(Q>q)=1−F(q)∼q−β(q→∞), and that the times of disturbances are distributed as a Poisson process.