Studies on Power Quality Problems and Design of Mitigation Techniques: Case Study- Africa PLC (Macaroni and Pasta Factory

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Addis Ababa University


This thesis presents assessment of power quality problems of Africa PLC (Pasta and Macaroni) factory which is located in Adama town about 80km from the center of Addis Ababa towards east. The assessment investigates the major electrical phenomena that disturb the power quality of this particular factory. As such, almost the majority of power quality phenomena listed by the IEEE Standard 1159-1995 are assessed in this thesis. The necessary data are collected from the factory through direct measurement using harmonic analyzer as well as from recorded data at Adama substation. The collected data are analyzed and the results are then compared with the IEEE standards to identify the type and level of the power quality problems. The analysis of the harmonic distortion has indicated that the worst individual harmonic distortion of 25 % 5th and 22.5 % 7th harmonic components have been existing in the power distribution system of the factory. Again, it has been observed that the factory has been working with poor power factor which is 0.78. Consequently, shunt harmonic filters that have an added feature of power factor correction are designed to reduce the amount of current harmonics and for upgrading power factor. With the designed shunt harmonic filters the dominant harmonic components (5th and 7th) are reduced to less than 4% and average power factor has been upgraded to 0.96.Further the cost analysis of the designed mitigation system showed economic feasibility of the solution as it would take only 2 years and 9 months to repay the total cost involved in the proposed mitigation techniques. The modeled systems with and without shunt harmonic filter have been simulated using Mat Lab /Simulink software to verify the improvements achieved in terms of power quality. The result showed significant improvements. It is concluded that the problems like harmonic distortion, power factor and power interruptions are severe compared with the standard values whereas the rest of the power quality issue like power frequency variation, voltage fluctuation, voltage unbalance, and current unbalance are within the allowable range. Furthermore the reliability analysis, it has been seen that the factory has been facing frequent power interruption. Recommendations are forwarded to EEU concerning the issue of power interruption. Key Words: Power quality, Harmonics distortion, Harmonic filters, Mat Lab/Simulink, power factor, power interruption, reliability.



Power quality, Harmonics distortion, Harmonic filters, Mat Lab/Simulink, Power factor, Power interruption, Reliability