Calibration of power flow measurements

Power systems are monitored by measuring the line power flows, bus voltage magnitudes and bus power injections. The real-time data are sent to various control centers and planning groups. So the reliability of a power system, the economy of its operation and the adequacy of its forecasting require accurate measurements. Yet these real-time remote measurements include errors caused by many factors, errors that affect the quality of state estimation solutions. A method is proposed to make up for the measurement errors and provide scale adjustments, that is, remotely calibrate real and reactive powers and voltage measurements. This approach requires information concerning the network configuration, the impedance of all lines, and reliable data measurements at a few points of the system. The proposed algorithm consists of determining calibration constants for the various measured values by using alternately bus power balance and line power loss, starting from reliable points and propagating the process throughout the network. Finally, the measurements are corrected (calibrated) by means of those calibration constants for all hours at which they were taken.