The impact of energy efficient lighting on power networks.

Abstract

The power utilities in many countries have come under stress as a result of generation capacity deficits, looming fuel costs and in many developing countries the electricity demand is very quickly outstripping the available electricity supply [1]. Since 2006, Eskom has been utilizing large scale residential efficient lighting roll out programmes as a cost effective short to medium term supply security solution while the longer term capital intensive supply side, “Build Programme” was underway [2]. This mostly involved the use of non-linear compact fluorescent lamps (CFLs) to replace linear incandescent lights (ILs) with very little involvement and influence by the utility QOS (quality of supply) engineers that are responsible for ensuring supply quality on the specifically targeted Distribution networks. This dissertation highlights that while CFLs can provide the desired energy or peak power reduction required, they can also have an impact on QOS within specific sensitive networks if the appropriate CFL standards (i.e. IEC 61000-3-2) minimum requirements are not adhered for both power factor and harmonics. These large scale CFL implementations have cost implications and hence metering and verification methods and models have been developed to simulate and quantify the returns from investing in energy efficient lighting initiatives. CFL manufacturers differ on ballast designs which have a direct impact on lamp efficacy, harmonic distortion and power factor which contribute to network quality of supply. It is for this reason that this dissertation raises an awareness of the importance of appropriate CFL standards i.t.o. the impact on quality of supply from a harmonics and power factor perspective. Due to the lack of more recent available or reliable sources of CFL test data, laboratory investigations were used to confirm the harmonics and PF characteristics of a variety of commercially available CFLs in addition to those utilised in previous large scale rollout programmes. The harmonics and power factor performance measured were compared for compliance against the international limits as prescribed in IEC 61000-3-2. Further investigations on international lighting industry standards for CFL’s has revealed gaps pertaining to harmonics and PF limits. This study is concluded by highlighting the impact of CFLs on power networks. It also provides a brief guide for utility power quality engineers by imparting an understanding of their role for the large scale efficient lighting programmes in order to pro-actively contain any possible impact on quality of supply within the regulatory limits as prescribed in the QOS standards.