On estimation of uncertainties in analog measurements [of power systems]

A range of measurements is obtained from a substation that spans peak-load and light-load conditions and includes bus voltages, phase angles and line flows. Then the redundancies in measurements are used to formulate several functions relating these measurements to their attending errors. Minimization of these functions yields the required corrective coefficients. Specifically, the instruments, their arrangement and their characteristics for the 69/13.2 kV South Athens substation of the Athens Utilities Board, are described. Then an error analysis is presented showing the various sources of random uncertainties in the analog measurements. Next the redundancies in the measurements are used to establish several functions whose minimizations provide the required corrective coefficients. This is followed by estimation of propagation of random uncertainties and evaluation of the systematic errors