Improving the extent of correlation between interharmonic and voltage fluctuation measurements

Because the use of 60-W incandescent lamps is declining in parts of the world, voltage fluctuations' effects on other devices may need to be explicitly considered in international standards. The existence of international standards for measuring interharmonics and the mathematical relationship with periodic amplitude modulation has suggested interharmonics as a potential basis for broadly characterizing voltage fluctuations. But any novel approach for measuring voltage fluctuation needs to provide results consistent with present practices in addition to offering additional advantages. Therefore, the first step is demonstrating a general correlation between interharmonic measurements and currently accepted flicker severity measurements. The feasibility of demonstrating the correlation between these measurements has been explored in an earlier work. Using a magnitude-only custom interharmonic group it was concluded that measurements were strongly correlated in most cases. A closer examination of the flickermeter is made in this paper, and an improved custom interharmonic group is developed in view of a flickermeter's response to the combined effect of interharmonic pairs through phasor addition. This approach revealed strong correlation for every dataset examined. It is concluded from these results that interharmonic and lamp flicker measurements are strongly correlated in general.