The 2012 World Congress on Power and Energy Engineering (WCPEE'12) Reference Number: 000 1 Sources and Mitigation of Harmonics in Industrial Electrical Power Systems: State of the Art A. Y. Abdelaziz S. F. Mekhamer Electrical power and machines Department Faculty of Engineering, Ain Shams University, Cairo, Egypt Sherif M. Ismael Electrical Engineering Dept., Engineering for the petroleum and process industries- ENPPI, Cairo, Egypt Abstract – Power systems are designed to operate at frequencies of 50 Hz or 60Hz. However, certain types of loads produce currents and voltages with frequencies that are integer multiples of the 50 or 60 Hz fundamental frequency. These higher frequencies represent a form of electrical network pollutions known as ''power system harmonics''. This paper presents an extensive literature review in the petrochemical sector for the power system harmonics such as harmonics fundamentals, harmonics harmful effects on various electrical equipment, harmonic distortion limits and harmonic mitigation techniques. This paper is intended as a guide for those interested in this problem or intending to perform further researches in this area. Index Terms- Harmonics, Mitigation, Variable Speed Drives, Total Harmonic distortion, Point of Common Coupling. I. NOMENCLATURE VSD Variable speed drive VFD Variable frequency drive SMPS Switched mode power supply UPS Uninterruptable power supply SCR Silicon controlled rectifier PCC Point of common coupling THD Total harmonic distortion CT Current transformer VT Voltage transformer FFT Fast fourier transform STD Standard IGBT Insulated gate bi-polar transistor CAD Computer aided design PWM Pulse width modulation VSI Voltage source inverter FEED Front end engineering design LNG Liquefaction of natural gas SLD Single line diagram ESP Electrical submersible pump TIF Telephone influence factor WTHD Weighted THD APF Active power filter ETAP Electrical transient analyzer program TINA Pro Design and circuit simulation software II. INTRODUCTION ower system harmonics are not a new phenomenon. Concern over harmonic distortion has been introduced throughout the history of electric power systems. Steinmetz published a book in 1916 that devoted considerable attention to the study of harmonics in three- phase power systems. His main concern was third harmonic currents caused by saturated iron in transformers and machines, and he was the first to propose delta connections for blocking third harmonic currents. Later, with the innovation of rural electrification and telephone service, power and telephone circuits were often placed on common rights-of-way; accordingly Harmonic currents produced by transformer magnetizing currents caused inductive interference with open-wire telephone systems. The interference was so severe at times that voice communication was impossible. This problem was studied and treated by filtering and by placing design limits on transformer magnetizing currents. Today, the most common sources of harmonics are power electronic devices such as VSD, SMPS, UPS, and Static VAR Compensators. These loads use diodes, (SCRs), power transistors, and other electronic switches which chop the sinusoidal waveforms to control power or to convert 50/60Hz AC wave to DC wave and accordingly drew non-sinusoidal currents from the supply network. The work of J.B.J. Fourier (1768-1830) have been extensively useful for analyzing these non-sinusoidal waveforms, as it allows any periodic function to be described in a series of sinusoidal and co-sinusoidal functions, In 1920s and 1930s the AC/ DC converters were developed using mercury arc rectifiers, The invention of (SCR's) or thyristors in the 1950s, led to a P