EVALUATION CRITERIA FOR STREET LIGHTING CONTROL SYSTEMS
This document has been produced because of the many difficulties in deciding which lighting control system to choose. Its purpose is to enable an unbiased evaluation and comparison of both functional and technical intelligent lighting control systems and can form the basis for the preparation of Terms of Reference (ToR).
The document is based on the “Technical Specifications of the Control and Monitoring System to save energy, reduce maintenance costs and enhance maintenance efficiency on our Outdoor Lighting Network” prepared by LonMark – an organisation that defines standards for home and industrial automation control systems, bringing together the largest manufacturers of automation equipment and systems (www.lonmark.org). As this organisation consists mainly of manufacturers and users of the LonWorks standard, any reference to a specific platform has been removed with the permission of the author. This will allow the document to be used to evaluate a wide range of street lighting control systems.
INTELLIGENT LIGHTING CONTROL
Various intelligent street lighting control systems are available on the Polish market. The desired parameters for such systems are included in the EU guidelines, contained in the e-streetlight project (http://www.e-streetlight.com/).
It is worth pointing out that non-compliance with the guidelines adopted as standard constitutes a risk for the user of such systems. The reason is that it is not possible to expand the system with devices from other manufacturers, and if the devices are withdrawn from the offer, it is not possible to replace them with other analogous models and it is necessary to replace the whole system at a very high cost. Management software can also be a problem, as with closed solutions the user is always dependent on a single supplier, who in practice dictates prices. In the case of open solutions, there are always several suppliers, allowing the investor to choose according to the technical and price parameters that are better for him.
An example of standard solutions that are fully compliant with e-streetlight guidelines are systems using the LonWork standard. Compatibility with the LonMark standard allows the combination and interchangeability of products from different companies.
The basic functions of an intelligent lighting control system for roads, streets, squares and parks are:
- control of individual streetlights (HPS, LED or MH);
- switching on or off lamps and limiting their power;
- possibility of automatic modification of the expected lighting level depending on road conditions;
- possibility of independent control of different lamps of the same system, e.g. not reducing power in the vicinity of pedestrian crossings;
- counting the electricity consumption and operating time of individual lamps and groups of lamps and additional devices powered from the same installation, e.g. Christmas lights;
- control of electrical parameters of each lamp separately (voltage, current, power factor, active power, reactive power, etc.);
- control of proper operation of lanterns; in case of failure, the system can notify the operator and service teams of the need to respond, e.g. by sending an SMS;
- detection of unauthorized opening of lamp housing with notification to appropriate authorities;
- temperature monitoring capability of electronic devices in the lamp.
Savings – Smart Streetlights
The use of communication using existing power cables and standardised equipment (open protocols, interfaces, LonMark standard) allows investment costs to be minimised while maintaining maximum flexibility and efficiency. As a result, a very short payback time (2–4 years) can be achieved.
Additional savings can be achieved by using new high-efficiency light sources in addition to intelligent lighting controls. In the case of the city of Oslo, savings of up to 70% have been achieved with a comprehensive system upgrade, without the lighting being switched off as would be unacceptable by the standards. This installation is somewhat of a reference in Europe and is a model not only because it is the first installation of its kind, but it also shows that it is worth choosing open solutions in which the solutions of several companies work together successfully.