Power quality in public lighting systems

The governments are interested in applying energy saving policies. From this point of view, the energy consumption for lighting can catch up 15% of the total electrical energy country bill. As a matter of fact, the lights are often inefficient, they are used when is not necessary and they are also generator of a considerable amount of distortion. A possible method to reduce the energy consumption and to increase the Power Quality (PQ) level can be represented by the substitution of the old lamps and by using new ballast and control systems. The aim of this paper is, with reference to public lighting, to illustrate as the electronic control gear for traditional High Pressure Sodium (HPS) lamp makes possible not only energy saving but also a wide PQ improvement.