A Study on Harmonic Load Design Methods Based on NEC and IEEE Standards for Power Quality Improvement

The Harmonics have emerged as one of the major causes of power quality degradation in modern electrical systems, and their impact is becoming increasingly severe due to the growing presence of nonlinear loads. Harmonics distort voltage and current waveforms, leading to problems such as equipment overheating, malfunction, and reduced lifespan, ultimately compromising the stability and reliability of power systems. Therefore, the proper design of power feeders that account for harmonic-generating loads is considered a critical task.<br/>This study investigates power feeder design methods capable of effectively addressing harmonics, based on the National Electrical Code (NEC) and the Institute of Electrical and Electronics Engineers (IEEE) standards. The analysis focuses on IEEE Std 519 for harmonic limits and examines relevant NEC provisions related to conductor selection, overheating prevention, and neutral conductor overcurrent.<br/>Additionally, through case studies of power quality issues caused by harmonics, this paper outlines key design considerations and presents technical countermeasures such as harmonic filters, mitigating transformers, and specialized cables. This review aims to provide practical design guidance for engineers to ensure the stability and efficiency of electrical installations in harmonic-rich environments.