The site 450 kVA load is actually a three-phase, six pulse thyristor rectifier feeding a dc bus. Assuming that the voltage waveform at the site 11 kV bus is purely sinusoidal, calculate the Total Harmonic Distortion (THD) at the 415 V point of common coupling. Is this level of harmonic distortion acceptable?
The site engineer has decided that a 75 kVA three-phase power factor correction capacitor bank should be connected across the incoming ac supply to improve the sites' power factor and to support the local voltage level.
Calculate the Total Harmonic Distortion at the 415 V point of common coupling for this new circuit arrangement.
Is this new level of harmonic distortion acceptable? If not, give a brief view on how might you go about solving the problem?