Power losses in public lighting grid

Public lighting in the Czech Republic consumes annually about 700 GWh. Transmission of this energy is naturally connected with losses, which are covered by municipalities. Losses are determined by cable properties and squared current. The range of current is determined by luminaires itself: as compensation capacitor in discharge lamp luminaire ages, reactive current in supplying wire increases. This reactive current causes Joule's losses. Moreover capacitors are usually not subject of maintenance. Also right balancing of load evenly in 3 phases reduces losses in wires and circuit breaker size can be reduced. Based on series of measurement in city of Ostrava the authors try to calculate potential savings in lighting network distribution grid. Main goal of the article is a recommendation of measures, which should be done to save money by reducing Joule's losses and estimate possible impact in local and national scale. (Power losses in public lighting grid)