Power Factor Correction and Harmonic Mitigation for a Heavy Industrial Nonlinear Load

The paper reports a technical solution for both the reactive power compensation and harmonic attenuation of an especial low-voltage heavy industrial application. The latter mainly consists of a large nonlinear load with 2.9 MW rated power that operates at 765 V. These rather uncommon data for the consumer are to be found in specific chemical or metallurgical processes. After a proper investigation of the load power quality issues, an active filter solution is proposed and correspondingly applied. Thus, four special designed active harmonic filter (AHF) connected in parallel were selected, each of them with rated current of 300 A. They constantly ensure the power correction, simultaneously with the voltage and current harmonic mitigation in accordance with actual standards and regulations. Supplementary, line reactors and an autotransformer that manages to adequately supply the active filters at their rated voltage were also designed. The proposed solution was validated by the power quality measurements. The solution could be extended for other similar heavy industrial consumers, where large reactive power circulation and waveform distortions are to be synchronously addressed.