Impact of current phasor measurement configuration on power system state estimation

Current phasor measurements have become increasingly available in modern power systems due to the development of advanced metering systems, including synchrophasor technology. The configuration of these measurements, particularly the installation point of the metering device (whether on a bus or a branch), which determines the measurand (injection or flow), significantly influences the operation of power system state estimators (PSSE). This paper aims to assess the impact of different current measurement schemes on the well-established weighted least squares (WLS) PSSE method, by investigating its performance in terms of convergence and accuracy when using current flow or injection data, as well as a mix of both. Additionally, practical considerations related to technical installation issues, such as the circuit-level measurement point and the utilization of instrument transformers, are discussed. The findings from this analysis demonstrate that the configuration of available current measurements strongly affects the quality of PSSE. Therefore, explicit planning of relevant metering schemes is required to ensure optimal performance.