Harmonic Distortion Analysis in Thyristor Rectifier System in Aluminum Smelting Industry and Its Mitigation Strategy Based on IEEE STD 519

Abstract

Thyristor-based rectifiers in the aluminum smelting industry produce harmonics that can degrade power quality and affect the reliability of the electrical system. This study aims to analyze the harmonic characteristics of 6-pulse and 12-pulse rectifiers, examine their relationship with the IEEE Std 519-2022 criteria, and evaluate mitigation strategies. The study uses a literature study method with a descriptive quantitative analysis approach. The population and sample of the study are not defined in the form of respondents, but rather in the form of scientific literature and technical publications relevant to rectifier harmonics, power quality standards, and harmonic mitigation. The research instrument is in the form of literature documentation, while the analysis is carried out through the identification of harmonic orders using the equation (h = kp \pm 1), wave reconstruction based on Fourier series, Total Harmonic Distortion (THD) estimation, and conceptual comparison with the Total Demand Distortion (TDD) criteria. The analysis results show that the theoretical current THD of the 6-pulse rectifier reaches 31.1%, while the 12-pulse configuration reduces it to 15.3%. Mitigation strategies studied include increasing the number of pulses, passive harmonic filters, and shunt active power filters. Conclusion: THD reduction can be achieved through the selection of rectifier configurations and the application of filters, but compliance with IEEE Std 519-2022 must be verified through TDD measurements and the Isc/IL ratio at the common connection point.