Harmonics Source Identification Analysis using Spectrogram for Rectifier Load

Abstract

The increasing of power electronics equipment contributes to the poor quality in power system. One of the major issues of power quality problem is harmonics distortion. A poor quality of electrical supply will affect the manufacturing process, malfunction of equipment and economic losses. Thus, it is important to trace and identify the harmonic source in power system so that precaution action can be taken appropriately. This paper aims to identify and analyze the harmonics source in power system using spectrogram technique. The sources of harmonic will be focused in this study is rectifier. The information of the harmonic characteristic obtained from the proposed technique will be presented in the time-frequency representation (TFR). From the TFR the signal parameters such as instantaneous root means square (rms) voltage, instantaneous rms current, spectrum of voltage and spectrum of current will be extracted. Next, these signal parameters will be used to identify the characteristics of harmonics source by using TFR of impedance. The signification finding of this research shows the harmonic sources location can be identified by referring to the relationship between fundamental impedance (Z1) and harmonic impedance (Zh).