OPTIMAL PLACEMENT OF PMUs FOR POWER SYSTEM STATE ESTIMATION

Abstract

A Phasor Measurement Unit (PMU) is an electrical measurement device which can measure voltage phasor of a bus at which it's placed and the branch current phasors of the connected lines. Since, bus voltage and branch current phasors (voltage magnitude and angle) are measured, the state estimation equations become linear and it is easier to find the solution than the nonlinear system state estimation. Since, installation of a PMU and its branch current phasors are very costly, one cannot place PMUs on each and every bus in the power system but are placed at few optimal locations. Hence optimal PMUs placement problem is one of the important and popular subjects in power system now days. The fundamental contribution of this dissertation report is the introduction of two new techniques to minimize the number of branch current phasor measurements that need to be measured by PMUs still satisfying complete observability. This report starts with the optimal PMUs placement problem and its formulation for different cases using Integer Linear Programming. The cases include optimal placement of PMUs for Complete and Incomplete observability, optimal placement considering Zero-injection buses, optimal placement against measurement loss and branch outage, optimal placement for bad data detection etc. Then the report introduces the two new techniques to minimize the number of branch current phasor measurements — a searching technique and an optimization technique. Simulations have been carried out using the Binary Integer Programming function of Matlab on IEEE-14 and IEEE-30 Bus systems for verification of the placement problem as well as the new technique.