Surge protection concepts for LED street lighting systems

Long lifetime of LEDs, reduction of maintenance work and replacement costs

Street lights are currently being retrofitted in many cities, communities and municipal utilities. In this process, conventional luminaires are frequently replaced by LEDs. The reasons for this include, for example, energy efficiency, removal of certain lamp technologies from the market or the long lifetime of the new LED technology.

To ensure longevity and availability and to avoid unnecessary maintenance, a suitable and particularly efficient surge protection concept should be incorporated at the design stage. Although LED technology has a lot of advantages, it has the disadvantage over conventional luminaire technologies that replacement costs for equipment are higher and the surge immunity is lower. An analysis of surge damage to LED street lights shows that in the majority of cases not individual, but several LED lights are affected.

The consequences of damage become evident in partial or complete failure of the LED modules, destruction of the LED drivers, reduced brightness or failure of electronic control systems. Even if the LED light is still operational, surges normally negatively affect its lifetime.

Sample protection measures:

• Type 1 combined arrester in the cable distributor (e.g. DEHNshield)
• Type 2 surge arrester in the cable junction box (e.g. DEHNcord)
• Connection of the metal mast to earth

Variants overview DEHNcord
DEHNcord L type DCOR L...	3P 275 SO LTG	2P 275 SO LTG	3P 275 SO IP	2P 275 SO IP
Degree of protection	IP 20 integrated in a fuse box		IP 65 Installation outside the fuse box
Protection of the control phase	yes	no	yes	no