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Anibal T. De AlmeidaOvercoming Problems With Harmonics and Low Power Factors Dep. Eng. Electrotecnica, Universidade de Coimbra, Portugal Abstract The use energy-efficient discharge lamps (fluorescent, sodium, etc.) can lead to substantial energy and capacity savings. However, it must be ensured that the lighting loads present a high power factor and do not inject large amounts of harmonics in the network. Otherwise there will be negative impacts, both for the utility and customer, which will decrease those savings. Discharge lamps have non-linear current-voltage characteristics which give rise to harmonics. Traditionally discharge lamps have been used in conjunction with iron core ballasts which can also produce a poor power factor. The paper describes how these problems appear and suitable mitigation measures. Electronic ballasts are increasingly being used both in conjunction with long tubes and with compact fluorescent lamps due to their higher efficiency and overall superior performance. The power electronic devices in the electronic ballasts generate harmonics and sometimes a poor power factor. This applies especially to compact fluorescent lamps due to space/weight/cost limitations. The paper presents an assessment of the performance of electronic ballasts, with relation to power factor and harmonics. The impact of recent developments in microelectronics in electronic ballast performance is also analyzed. Recently low-harmonic modular type compact fluorescent lamps have been introduced into the market, which deserve to be promoted due to their lower overall life-cycle cost and better performance. In order to ensure the penetration of low harmonic distortion lighting equipment into the marketplace, standards are being introduced in Europe and the USA. Additionally, the need for incentives to promote equipment whose characteristics surpass the standards is discussed.
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