Optimal Placement of Phasor Measurement Units for Improving Power System State Estimation Accuracy: A Heuristic Approach

This paper describes a heuristic approach for optimal placement of phasor measurement units (PMUs) in power system for improving state estimation accuracy. PMUs are able to measure highly accurate bus voltage phasors as well as branch current phasors incident to the buses at which PMUs are installed. Due to cost consideration of PMU placement, power grid utilities are interested in the knowledge of how to add a limited number of PMUs to their existing network in order to improve state estimation performance. State estimation results are calculated by the weighted least square (WLS) state estimation method. In the problem of adding PMU measurements into the estimator, two methods are investigated. Method I is to mix PMU measurements with conventional measurements in the estimator, and method II is to add PMU measurements through a post-processing step. These two methods can achieve very similar state estimation results, but method II is a more time-efficient approach without modifying the existing state estimation software. The proposed PMU placement approach is tested using IEEE 14-bus system, and the obtained figure and table might help planning engineering determine the optimal placement of PMUs when they want to place a few PMUs in their systems.