Evaluation of measurement uncertainty in determining the supply voltage, dips and swells, in low voltage

The knowledge power quality levels, through objective approach, is based on the accumulation as measurement information. For a more complete characterization of power quality parameters it is necessary that the measurement process to include in the set of specific operations and evaluation of measurement uncertainty. Measurement uncertainty is a specific parameter of measurement method and conditions under which measurements are made. By this way, IEC 61000-4 series regulations "Electromagnetic compatibility" include a number of clarifications concerning the purpose of determinations, the level of accuracy and the level of uncertainty to be measured power quality parameters. The issue of evaluation of measurement uncertainty of power quality parameters, is presented in this article as a methodology, exemplified experimentally by measuring the nominal voltage supply, dips and swell in power distribution networks.