Line power quality improvement for pulsed Electrostatic Precipitator systems

In this article the distortions caused by the pulsed operation of a group of power supplies (PS) feeding an Electrostatic Precipitator (ESP) are investigated, and means for improving the line quality are proposed. In order to reduce the Total Harmonic Distortions (THD) of the line current and also improve the loading balance between the phases, the pulses of the individual power supplies are scheduled and controlled together, so that the power consumption becomes more continuous. The proposed system optimization is experimentally verified with two commercially available ESP supplies, each having power capabilities of 120 kW. The study shows the advantages of the pulses scheduling strategy namely reduction of both reactive power consumption and line current peaks; better current THD; better power balance among mains phases; and better utilization of mains components.