Reducing energy consumption of street lighting

摘要

A process and switching device are disclosed for reducing energy consumption of street lighting networks, large lighting installations and the like that consist of several lighting appliances (7-9) having each at least one lamp (10-15). During a first time interval (T, T', T'') (total switching time), the networks or installations are connected to an energy source (1), and during a second predetermined time interval (t1+t2) within the total switching time (T-T'') the power of at least part of the lighting appliances (7, 9) is reduced. In order to dispense with supplementary control lines for reducing the power of the lighting appliances (7, 9), the lighting appliances (7, 9) are provided with a switching device (16, 17) that derives the corresponding switching signals from the total switching time (T) measured during a preceding period, for example the day before, taking into account the second predetermined time interval (t1+t2). Advantage is taken of the fact that the midway point between sunrise and sunset - which corresponds to half the total switching time (T/2) - is reached practically always at the same hour at a given degree of longitude. This hour, or an hour derived therefrom, is used as reference value To for determining corresponding switching signals.