PMU Optimal Placement Algorithm Using Topological Observability Analysis

State estimation aims to estimate the optimal state variables that can represent the current state of a system based on the measurement set in the power system. The PMU (phasor measurement unit) is a key technology that can directly improve the performance of the monitoring, control and state estimation in the power system. The PMU enables the direct measurement of state variables such as voltage magnitude and phase angle. It also makes it possible to synchronize the measurement set using the GPS time stamp. To improve the performance of state estimation, it is not economical to place PMUs on all buses in the power system, so the PMU optimal placement must be determined. PMU optimal placement can be expressed as a limited optimization problem that secures the observability of the system with the placement of minimal PMUs by identifying the locations at which the PMUs should be installed. In this paper, we present the development of a PMU optimal placement algorithm that can determine the observability by searching the spanning tree of the graph, by which a topological connection relationship is created by measurement set.