Analysis and Mitigation of Power Quality Issues. A Case Study: Assela Malt Factory.

Abstract

The Assela Malt Factory and other local clients in Assela face serious power quality issues, including frequent power outages, voltage fluctuations, harmonic distortion, low power factor, and voltage imbalance. These issues lead to equipment damage, production interruptions, increased energy costs, and reduced system efficiency. Notably, problems like motor overheating, PLC card failures, and light bulb damage have been observed. This thesis aims to evaluate these power quality challenges and propose a DSTATCOM-based solution using MATLAB/Simulink. The goal is to improve power factor, stabilize voltage, and mitigate harmonic currents. Implementing DSTATCOM will help the factory reduce reactive power charges, protect equipment, and enhance overall efficiency and system reliability. The Assela substation, Ethiopian Electric Utility (EEU), and the company provided critical data showing poor power quality on the industrial feeder, including a low power factor of 0.77, frequent interruptions, and high harmonic distortions. Source voltage and current THD were 3.38% and 6.39%, respectively, with nonlinear load-induced current and voltage THD at 22.28% and 13.84%. Voltage unbalance averaged 2.2%, and fluctuations reached 9.09%. After installing a DSTATCOM, THD values dropped significantly source current THD to 0.98% and load/source voltage THD to 1.55% preventing 12.1 kW in losses. Simulations in MATLAB/Simulink showed improved voltage levels and reduced current harmonics. The factory’s monthly penalty due to poor power factor was about 3,175.28 birr, which was avoided by improving the power factor to 0.98 lagging. This also reduced system power losses by 38.26% (for two transformers operating parallel) and 37.92% (for one transformer working alone). A cost analysis of the DSTATCOM implementation was also conducted.