Identification and Mitigation of Power Quality Problem Using Unified Power Quality Conditioner (Case of Wonji Showa Sugar Factory)

Abstract

Electrical energy is the most easily utilized type of energy, and demand for it has significantly expanded as a result of technological advancements. A power quality problem is the issue resulting in frequency, voltage, or current variations that cause utility or end user equipment to malfunction or fail to operate. Severe power quality issues, such as an excessive neutral current, harmonic currents, supply voltage imbalances, harmonic voltage flicker, voltage sags, voltage swells, surges, notches, and spikes are currently affecting power distribution networks. Because of a variety of causes, several industries were disturbed by the issue of poor power quality.Therefore, it would be beneficial to investigate and mitigate the problem that affects the quality of power in the distribution network. In this thesis, identification of voltage sag and harmonics as power quality problems and proposing the proper mitigation technique in Wonji Showa Sugar Factory (WSSF) at the Steam and Power Generation Plant (S&PGP) distribution network was presented. The Powerlogic PM800 device is used for the measurement of harmonic distortion level. The measured current and voltage harmonic distortion data at the distribution board is compared with Institute of Electrical and Electronics Engineers (IEEE) standards, and the obtained data showed that the current harmonic distortion level is above the standard limit and the voltage harmonic distortion level is below the IEEE standard limit. During the collection of data, the voltage sag was also found in the distribution network of S&PGP. In order to mitigate the problem found in the distribution network, Synchronous Reference Frame (SRF) theory based Unified Power Quality Conditioner (UPQC) was proposed. The effectiveness of the suggested mitigation strategy was evaluated by modeling the distribution network of the plant with and without SRF theory based UPQC as the proposed control technique using MATLAB/Simulink. As a result of load current harmonics, the source current Total Harmonic Distortion (THD) percentage was 20.19%, 20.11%, and 19.88% for phases 1, phase 2, and phase 3, respectively, and because a fault occurs in the distribution network, a load voltage drops to 0.8 p.u. With the addition of the SRF theory based UPQC, the load voltage became 1 p.u., and the %THDI decreased to 4.10%, 4.58%, and 5.55% for phase 1, phase 2, and phase 3, respectively. The simulation results show that voltage sag issues and current harmonics that occur in the distribution network have been reduced to below the IEEE standard limit with UPQC devices connected to the distribution network.