Impact of erroneous measurements on power system real-time security analysis

Power system security analyses as well as decisions made to preserve system security are all on the basis of an approximate insight over the system status. This approximate insight is provided based on erroneous measurements throughout the system. The error in the input data may result in a misleading index which either increases system operating costs or jeopardizes service continuity. This paper aims at establishing an step-by-step algorithm to study impacts of error in measurements on system security indices. Two different security indices representing under voltage severity and over load severity are studied in this paper. The proposed algorithm has three major steps. In the first step, typical measurements are sampled according to the system operating state and randomly generated errors. This is done using Monte Carlo sampling approach. The second step is to extract an approximate model of the system true state which is done via state estimators. Then, security indices are calculated for both the approximated and true states in the third step. Comparison between the indices demonstrates impacts of the erroneous measurements on security assessment.