An Accurate State Estimation Methodology for a Completely Observable Network with PMU Measurements

Abstract

A novel Kalman Filter State estimation is introduced which provides Dynamic State Estimation (SE) of the system. This paper discusses such state estimation techniques which may be employed to cater the need of monitoring and control requirement of modified power system. The best optimal location of phasor measurement units (PMUs) and to ensure minimum PMU requirement, complete network observability while maintaining best SE accuracy has been considered. Optimal locations are not unique to a system. But there may be other set or sets of locations having same n number of PMUs. All of these sets of optimal locations are explored and Kalman based SE is run for each set. The optimal locations set which results in the best SE accuracy is finally selected as the best location of PMUs which comply with observability as well as SE requirements of the network. The minimum number of PMUs required for complete observability is found to be 4 for IEEE 14 bus network. All the possible sets of optimal PMU locations (having 4 PMUs) are explored. The locations so obtained give best results both in terms of observability, minimum number of PMUs as well as SE accuracy. Each estimation method is developed in MATLAB and is tested on IEEE 14 bus test system to observe their feasibility. The results obtained from the simulations are compared based on estimation accuracy. The comprehensive comparison made in this paper may help researchers and engineers to better assess and employ the estimation technique according to requirement.