Experimental Determination of THD for Different Lighting loads

Abstract

With the advent of power electronic system in generating stations, sub-stations, transmission etc., the power supply are being contaminated in terms of distortion of voltage and/or current waveforms. Distorted waveform introduces harmonics into the system. These harmonics causes overheating for machines, transformer, capacitors and also telephone interference. To mitigate these problems it is necessary to understand the level of harmonic distortion. In this regard, the present work is a basic step to estimate Total Harmonic Distortion (THD) of different lighting loads. An experimental setup was prepared for this purpose and experiments were conducted for four lighting loads that are commonly used in practice. The waveforms of these loads were recorded and Fast Fourier Transform (FFT) has been used to determine Total Harmonic Distortion and Individual Harmonic Components of each load. The results obtained were compared with the standard specifications and found to be acceptable in case of Incandescent lamp and Florescent lamp whereas a considerable deviation was found for Compact Florescent lamp and High Pressure Sodium Vapour lamp.