Large Banks of Negative Differential Resistance Nonlinear Loads: A Hidden Threat to Power System Quality

Abstract

DSM (Demand Side Management) is a short term and comparatively low cost solution for energy starved countries. Replacement of IB (Incandescent Bulbs) with CFL (Compact Fluorescent Lamps) has proved its success throughout the world. The same solution, at larger scale, was proposed to Pakistan to mitigate power shortage on short term basis. Accordingly in year 2008, ADB (Asian Development Bank) conducted a study and it was found that replacement of conventional IB with 30 million CFL will result into series of benefits for the stake holders and above all the Environment. The study, unfortunately didn’t take enough consideration of effect of CFLs on the power system being nonlinear device and so the power quality issues remained a secondary consideration. The focus of this paper remains on the effect of such non-linear load on consumers, it also envisages the erratic behaviour of such large penetration of CFLs on direct single phase, three phase, digital as well as electromechanical energy meters, under different loading conditions e.g. resistive load, SMPS (Switch Mode Power Supply), half and full-wave rectifiers. It also reflects harmonic pollution caused by CFLs, their effect on power system quality and the registration ability of electromechanical as well as digital energy meters. To this end Harmonic spectrum was recorded up to the 31st harmonic.