Power factor correction and harmonics mitigation based on phase shifting approach

Abstract

The traditional approach to power factor correction in industrial applications involves installation of capacitor banks. But, with the widespread use of non-linear loads, such as variable speed drives (VSDs), power factor improvement has become more difficult. The presence of harmonic currents cause power capacitors to absorb them, as capacitor impedance is inversely proportional to frequency. The effects are overheating and increased dielectric stress of power capacitors, which result in their premature failure. Capacitors can also interact with harmonics, leading to harmonic amplifications at resonant frequency, which can damage the capacitors or components of the system. Besides, high power factor cannot be achieved because of distortion power. These have imposed the need for a different approach to power factor correction, i.e. application of harmonic solutions. High power factor and low harmonics go together. This article analyzes phase shifting technique for harmonics mitigation. Industrial case study is presented to demonstrate the applicability of the proposed technique for harmonics reduction and power factor correction at the same time. © 2012 IEEE.