Measuring active power, voltage and current using slow A/D converters

A new design of a digital measurement system based on the use of very slow highly precise and cheap A/D converters (dual slope) is described in this paper. Measurements of voltage and current are performed more than once in a period, so the measured value is reconstructed after n periods. Measurements performed on the electric utilities in Yugoslavia indicate that the voltage waveform remains unchanged while the required accuracy is maintained.