STATE ESTIMATION ALONG WLS-PHASOR MEASUREMENTS IN POWER SYSTEM

Abstract

Large Power System State Estimation, being a process to estimate voltage angle as well as the magnitude state for every bus of system of the power that is based on measurements which have been carried at only buses. The devices for the measurement of the earlier days, have only been able to give quantity measured magnitude. Nevertheless, a measurement device with the efficiency known as the Phasor Measurement-Unit (PMU) which is helpful for the measurement of the phasor of voltage (both magnitude a well as the angle) of a bus at which it’s placed as well as the phasors of current of directly connected lines are being used. Since PMUs are very costly, one cannot use PMU measurements only to estimate the state of a power system. Hence, phasor measurements are used as an additional measurement with traditional measurements to estimate the state of a power system. In this project report, use of PMU measurements to estimate the state of a power system has been explained and a MATLAB program has been coded as well as a simulation has been carried out on IEEE-14 bus and IEEE-30 bus systems for verification of the method. The method uses, a distinct estimator model of the linear state to use the estimate for the state from the WLS, as well as the current measurements and the PMU voltage through the post-processing. First the model estimates the state in polar coordinates using WLS state estimation method from conventional measurements. Then this state, with PMU measurements, both expressed in rectangular coordinates, is used to estimate the final state of the system.