Energy-efficient Street Lighting Using a Mitsubishi Alpha 2 PLC Based Solution

Abstract

The present paper deals with energy-efficient street lighting using LED technology. Depending on the voltage applied the LED luminous flux may vary. To ensure an efficient street lighting it is necessary to implement an on / off street lighting system schedule according to the geographical location by taking as a reference the times when the sun rises and sets for each day of the calendar year and to change the luminous flux of street lighting depending on the time of night. There are time periods during the night hours when the street lighting is very important, for example on the early morning hours or right after the sunset. In the remaining time periods luminous flux of LED lamps can be reduced after a well defined program. These goals can be achieved by using a Mitsubishi Alpha 2 PLC (AL2-10MR-A type) with four normally open contacts and by implementing a specific electric scheme at the street lighting system switching points.