HARMONIC ANALYSIS OF A NON-CONVENTIONAL HVDC SYSTEM

The advent of power electronics and proliferation of non-linear loads in industrial power applications, power harmonics and their effects on power quality are a hot topic of concern. Harmonics are the byproducts of modern electronics. They occur frequently when there are large numbers of personal computers (single phase loads), uninterruptible power supplies (UPS), variable frequency drives (AC and DC) or any electronic device using solid state power switching supplies to convert incoming AC to DC. Non-linear loads create harmonics by drawing current in abrupt short pulses, rather than in a smooth sinusoidal manner. The harmonics can be described as “a sinusoidal component of a periodic wave or quantity having a frequency that is an integral multiple of the fundamental frequency.” Some references refer to “clean” or “pure” power as those without any harmonics. But such clean waveforms typically only exist in a laboratory. This paper aims to compare the harmonic outputs of the conventional inverter and star-delta inverter. PSCAD/EMTDC software is used in simulation of the output harmonics of the mentioned inverters. Results show that the star-delta inverter gives similar output harmonic behavior like the conventional inverters.