Measurement of Subharmonics in Power Voltages

This paper presents the results of the monitoring of subharmonic voltages in a low-voltage distribution network using an IEC harmonic measurement instrument. The time evolution and the statistical analysis of the r.m.s. voltage magnitude of the subharmonic group and subgroup, defined as grouping of the output bins of an IEC harmonic measurement instrument below 50 Hz, are investigated in a low-voltage distribution system. The results obtained show higher magnitude of these components than was expected, showing similar time evolution to the magnitudes of the 1st and 2nd order interharmonic groups and the flicker severity indices simultaneously measured in the same power supply system.