Evaluation of the Uncertainties in the Measurement of Distorted Power by Means of the IEN Sampling System

摘要

A method for the uncertainty evaluation in the measurement of power in distorted signals is described. The power is obtained by a sampling system, which acquires the voltage and current and computes the power from the harmonic components obtained by the best fit. An equivalent algorithm is applied to derive a simplified relation between the correlation matrix of the harmonics and that of the samples. The uncertainties are then evaluated by a model of the uncertainty of a single sample given by the manufacturer of the sampling voltmeters.