Power Quality and Harmonics of a Grid Network
Osunde, O.D

Department of Electrical/Electrical Engineering

University of Lagos, Lagos, Nigeria.

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The present day electricity generation in Nigeria by conventional means can no longer satisfy the ever growing population, hence the need for embbeded generation to meet the demand. The Federal Government of Nigeria has set up the Independent Power Projects (IPP) to compliment the efforts of the Government by generating energy through renewable process which is expected to be evacuated to the National Grid. With the high rate of industrialisation in the Steel and Rail sector of the Nigerian economy, particularly with the upcoming Ajaokuta Steel company in Kogi State and the Delta Steel Company in Delta State and also with the re – awakenning rail transit system in Nigeria where large numbers of drives are expected to be used will bring the harmonic problem to the fore when connected to the Grid system. Harmonics are created by the non – linear operation of the semi – conductor devices of the drive and the non – sinusoidal nature of AC Suppy. Its effects include mal – operation of equipment connected to supply, over heating of transformers, cables and switchgear, telephone interference and a low power factor. In this work, a novel Pulse Width Modulation (PMW) scheme is presented. Analysis show that only the fundamental harmonic content is present while other lower harmonics are completely eliminated. The result is also verified by simualation and laboratory experiment. The problem of poor input power factor has also been addressed to reduce the level of penalty that is incurred for the consumption of reactive power.


Keywords: Renewable, Embbeded Generation, IPP, Harmonics, PWM, Simulation, Power Factor.