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How to plan street lighting control systems?

 

Utilizing LED lights are the fastest and easiest way to decrease  luminaires’ energy consumption. However, the use of LED lights will only solve the first half of the energy savings equation. The other half is related to controlt systems, which can significantly increase cost savings.

The key decision making principle lies in the choice of motion-based (dynamic) or preset (static) control systems.

With the motion-based system, it is certain that the initial investment is a bit more expensive, but at the same time street lighting can be managed by real-time traffic. On roads with low traffic density, it can substantially increase energy savings, since (a) luminaries only work at full power in case of motion ; (b) during the traffic-free period, lights can be switched to a minimal operating mode (e.g. 10% of nominal power). At the same time, in case of high traffic density, savings could be marginal, as luminaires must work at full capacity for most of the time.

Therefore, in case of high traffic density, it is worthwhile to use static control systems that allow lower-power modes to be set for low traffic loads.

In the latter case it should be taken into account that drivers and pedestrians must also accept less light while the dimming mode is switched on.

Therefore, if lighting is primarily performing road safety functions, we may have to consider not using any controlling or dimming solutions for the luminaires.

In the third, and in many cases, the most reliable option, consideration should be given to motion-based and static management systems in such a way that sections with higher traffic density are controlled by static dimming; whereas in case of lower traffic density, motion based controlling is preferred.

All in all, the planning of a management system should be guided by two core rules:

(a) Requirements must be drawn up according to the specific environment in which the lighting is used (including traffic density, road class, sidings, crossings, etc.).

(b) While assessing the profitability of an investment, in addition to the initial investment, the life-time costs of the solution must also be taken into account. As luminaires and control systems have a life span of over 12 to 15 years, in the long run, it is more cost-effective to look for cost-effective solutions with low fixed costs in any case.

Feel free to contact us if you would like to discuss more on street lighting and control systems!

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