Street Lights Are Currently Being Retrofitted

Street lights are currently being retrofitted in German communities and municipal utilities. In this process, conventional luminaires are frequently replaced by vLEDs. The reasons for this include, for example, energy efficiency, subsidy programmes, removal of certain lamp technologies from the market and the long lifetime of the new LED technology. To ensure longevity and availability and to avoid unnecessary maintenance, a well-conceived surge protection concept for LED lights should be incorporated at the design stage where the foundations for an efficient protection concept should be laid.

Although LED technology has a lot of advantages, it has the disadvantage over older luminaire technologies that replacement costs for equipment are higher and that LEDs are more susceptible to surges.

Surges can be caused by:
¨ Direct lightning strike to the luminaire, supply line or periphery of the street light or
¨ Indirect lightning strike which causes conducted interference in the supply line as a result of capacitive or inductive coupling or
¨ Surges resulting from switching operations, earth faults/
short-circuits or tripping of fuses

An analysis of surge damage to LED street lights shows that inthe majority of cases not individual, but several LED lights are affected by the causes mentioned above. Luminaire manufacturers and users such as municipal utilities or communities frequently cannot find the cause of damage.

Therefore, 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.

Consequently, the predicted lifetime cannot be ensured in practice and the LED light must be replaced earlier. These unscheduled costs lead to additional expenses and usually have not been considered in the amortisation of the project.