Simultaneous measurement of harmonics, interharmonics and flicker in a power system for power quality analysis

This paper considers two different aspects of power quality: on the one hand the correlation between interharmonic and sub-harmonic amplitudes and flicker in voltage supply and, on the other hand, the effect of harmonic distortion on the voltage tolerance of equipment. To deal with the first aspect, simultaneous measurements of interharmonics and flicker in voltage supply were taken in a low voltage distribution system. From the results obtained it may be concluded that low order interharmonic and sub-harmonic components in voltage supply can be used as an indirect method to predict the flicker levels. To study the second question, several laboratory tests have been made to obtain the voltage tolerance of equipment under different supply conditions. The results show that the voltage tolerance of equipment varies over a wide range depending on the harmonic distortion in voltage supply.