A digital instrument for measurement of voltage flicker

The voltage flicker is one of the aspects of power quality related to slow and repetitive fluctuations (0,5-30 Hz) of the rms voltage of the electricity supply network. To evaluate these fluctuations the UIE&IEC give functional and design specifications for a flickermeter. The proposed measurement techniques are basically designed for analog implementation. In this paper, a digital flickermeter is presented based on the forward and inverse F.F.T. and on the filtering in the frequency domain for the implementation of the functional blocks of simulation of lamp-eye-brain response. The instrument, implemented with a NI acquisition board inserted on a PC and with a software developed with the LabView tools, samples the voltage and furnishes the instantaneous flicker level, continuously sampled at 2 kHz. Results of simulated and actual data are reported to validate the performances of the realized flickermeter compliant the specifications of the IEC 868 recommendation