Roman Dubnicka

Automated system of the measurement of electric parameters of luminaires and light sources at chosen operational conditions

Quality of electric power is influenced all supplied devices. Due to changes supply voltage are electric parameters what can influence their other features. Therefore for example luminaires are measured at different supply voltage to find out impact of supply voltage to the luminous flux. This paper concerns system of analysis at change of supply voltage on photometric parameters of luminaires. Designed system is appropriate for measurement of electric parameters of luminaires because for them description their behaviour at various level of supply voltage is complicated.

Classification system for lighting design under condition of mesopic photometry

However, recommended system for mesopic photometry was already stated in 2010 a lot of issues are still open to solve them with respect to assessment of the adaptation luminance which is required for the computation or determination of the mesopic photometric quantity for example luminance or illuminance. This is mainly dependent on visual field of observer and also value of this photometric quantity is different for various situations in scene of the visual field of observer. Especially it can be shown that in outdoor lighting system applications is determination of the adaptation luminance critical depending on situations on the illuminated area. For these measurements are appropriate image photometers which are able to provide full information about spread of luminance in the picture. Data from image are valuable for investigation of adaptation luminance in detail. The paper deals with various situations which occur on the road under public lighting to investigate of possibility of assessment of adaptation luminance from images provided by the measurement with the image photometer. The results can be used for creation of appropriate classification system for practice and lighting designer to allow calculation of the photometric parameters at roadlighting design.

Methods for correction of the LIDC by means of goniophotometers with rotating luminaires for different lamps

Goniophotometry is the fundamental measurement method for the measurement of spatial distribution of the light output of luminaires. The measurement results are represented by luminous intensity distribution curves (LIDC). This information is used by lighting designers for computation of photometric parameters to predict photometric values in real lighting installations. Therefore accuracy of the measurement of the LIDC is very important to provide the best information for other processing. In practice for this type of measurements various types of goniophotometers can be used according to recommendation CIE 121:1996. The main purpose of the recommendation is to describe the different types if goniophotometers and to give recommendations to the measurement process. Currently this document is under revision to implement the new approaches in the field of goniophotometry. One of the most common type of instruments is the goniophotometer with rotating luminaire. Due to the simplicity of construction, moderate space requirements and favourable price most of the testing laboratories are using this type of goniophotometer for measuring LIDC of luminaires. There are possible errors present due to work position of luminaire in Earth gravitation field is changing by rotating the luminaire around its axis. The CIE recommendation tells if this type of goniophotometer is used correction should be applied e.g. by means of auxiliary photometer or other possible methods. The auxiliary photometer during the actual measurement can shade luminous parts of the luminaire what can influence the shape of the LIDC and also the derived photometric results. This paper deals with investigation of the correction methods in goniophotometric measurements using luminaire rotating goniophotometers. Results of measurements of LIDCs were validated by means of other type of goniophotometer which did keep the work position of the luminaires (mirror goniophotometer) during measurements. Conclusions of this work should provide recommendation for methods of corrections in goniophotometry of LIDC of luminaires which LIDCs are measured with luminaire rotating type of goniophotometer. Furthermore paper reveals the possible errors which can occur in the measurement of LIDC of luminaires with various types of lamps.

Influence of the calculation grid density to the selected photometric parameters for road lighting

Calculation and measurement of performance parameters of public lighting are performed in a grid of points defined by the CIE publication 140 and European standard EN 13201-3. Calculation grid defined in these documents was created at a time of low powerful computers and less precise measuring technology. Distance between two adjacent calculating points may be a 3 m, depending on the geometry of the road. This arrangement is sparse view of the fact that the present used computer can cope with much more denser grid in a short time and the measurement can be performed by the luminance analyzers. Between the results of the calculation with different grid densities of calculation points may be significant differences. This fact may influence the new optical systems and some LED luminaires which as found by measurement may contain various local extremes in the light intensity distribution curve. In calculating of performance parameters of public lighting and given the current used grid density these extremes may fall between calculation points and thus may not be included in the calculation. The solution is to propose a new density of calculation points which would be designed with respect to current possibilities of computer and measuring technology. The paper deals with the influence of grid density to the resulting photometric parameters of public lighting. In computing software will be used calculation grid of points according to EN 13201-3 and calculation grid with densification of calculation points in order to capture given local extremes to the resulting parameters The results will be used in the preparation of future revisions of normative documents, which provide a method for determining points of calculation and measurement grid.

Comparison of luminous intensity distributions measured on luminaire turning and mirror goniophotometer

A goniophotometer is needed to measure the luminous intensity distribution of luminaires. Goniophotometer types differ basically how their axes relate to the optical axes of the luminaire under test and in which order they apply the turnings. As the result one gets luminous intensity distributions in different coordinate systems, but those can be transferred into each others system. Some light source types like gas discharge types based on their operation principle are not allowed to measure them other then in their operation position. There are some light source types which operate independent from their operating positions. Such light sources are for example the semiconductor based light sources, like the LEDs. Some specially designed high power luminaires (like luminaires for sport lighting) can have forbidden operating positions which also are not allowed to measure with luminaire turning goniophotometers. The opinions about the right method are different also inside professional lighting communities. It is often complaint when such measurements are done that the luminaire is operated other than its original burning position and therefore the thermal conditions change inside the luminaire which results false data according the luminous intensity distribution and also its total luminous flux. The comparison is based on measurements carried out both on luminaire turning and mirror goniophotometer. Based on our experience the rotation of an LED luminaire is not causing definitely a worse cooling. To proof this experience thermal sensors are placed and monitored on the luminaires during both types of measurement. The aim of the paper is to show the observed differences on the different luminaire types in their luminous intensity distributions and their total luminous flux values when measured on different goniophotometer types.

Comprehensive view of LED products in luminaires

Nowadays, the LED technology is still more and more forthcoming technology. LED luminaires slowly replace traditional luminaires because their energy consuming in comparison with light output expressed by means of luminous efficacy lm/W increase to higher values what certainly save electrical energy consumption. At the present the popular way traditional light sources are replaced by LED retrofit lamps which has socket as traditional fluorescent lamps or light bulbs which can be easily mounted into traditional luminaires. The users are requested by LEDs, and they often do not realize the impact of exchange in a conventional lamp. The paper deals with electrical and photometric characteristics of LED retrofits, which are intended as a replacement for linear fluorescent sources. The above is a detailed analysis of the electrical wiring and also is shown the difference in SPD of individual light sources.

Analysis of non-recoverable lighting loses of luminaires

Maintenance factor of lighting system is hot topic in the lighting engineering. At the present is still not solved the question about used luminaires and degradation of materials in time from which consist the body of luminaire. Maintenance factor as parameter for practical maintenance of lighting system is very important aspect for design of lighting system from the level of the project to real installation. The paper deals with measurement system of obsolete luminaires with various optical systems. By the described procedure in the article is possible determine percent ratio of non-recoverable lighting loses which are undoubtedly very important part of the maintenance factor. Enon-recoverable lighting losesven more the paper describe the non-recoverable loses of various optical systems mounted in the real luminaires as diffuser, prisms, opal, frosted and clear optic.

Change of the spectral power distribution of luminaires under various electrical conditions

In general spectroradiometric measurements are very important part of characterisation of photometric or colorimetric parameters of luminaires. Street luminaires are installed in the outdoor conditions and can be operated under various electrical conditions depending on quality of the electric power. Electrical parameters may not always be ideal. Some disturbances in the electricity grid can occur. These disturbances can negatively influence output even photometric or colorimetric parameters of these luminaires. Investigated parameter in both cases is spectrum of luminaire. In paper is investigated influence of simulated of various supplied electrical conditions on some type of street luminaires. Especially the most effort is focused on spectral changes of output luminaires supplied with artificially simulation by stabilized of power supply. Presented results discuss extent of effect on described parameters above.

Calculation of Roadlighting Photometric Parameters Under Mesopic Conditions

At the present the mesopic photometry is hot topic in lighting engineering especially in the public lighting. The mesopic photometry is used in particular to consider roadlighting photometric parameters where mesopic vison is relevant to car drivers and pedestrians. Nowadays, works in the framework of the joint technical committee JTC001 at CIE is focused on mesopic photometry application. Within JTC001 there are two groups which are assigned to solve the stated problems. The first of them concerns fundamental problems on the processes of mesopic vision. e. g. adaptation luminance, field of view, pupil diameter of the eye etc. The second group follows the results of the first group. It should provide practical solutions in the mesopic photometry. One of this topic is devoted to roadlighting calculations. Methodology of roadlighting calculations is laid down in the document CIE 140:2000 which is currently under revision at CIE Division 4 (TC 4-15). Calculations are still based on photopic vision, i. e. photopic photometric quantities what disqualifies some innovative light sources mounted into luminaires which could be more efficient than traditional light sources if taking into account the mesopic conditions. It means that the old approach suppresses the usage of these luminaires because it does not consider appropriately the processes in the mesopic region where efficiency of the human eye is different. It depends on particular situation on the road and it is influenced by many other parameters. Therefore, new approach in the roadlight calculation emerged as a necessity for lighting engineers, who deal with roadlight, to consider mesopic conditions. Some preliminary results have been published in papers dealing with calculations based on the S/P ratio. This paper deals with roadlighting calculations assuming the mesopic photometry applied for various situations on the road with different roadlight luminaires and different light sources. Detailed analyses of possibilities how to use the mesopic photometry in practical calculations of photometric parameters of roadlighting for selected situations and luminaires are also presented in the paper..

Energy performance numerical indicators of public lighting

Energy performance assessment for lighting systems is recognized as an important tool for promotion of energy efficient lighting technologies. Based on European directives, components of lighting systems are subjected to eco-design requirements, and lighting systems in buildings are evaluated for energy performance. Now, similar activities are running in the field of public lighting. This paper brings a brief state-of-the art in the standardization process and aims to inform about partial research studies which have to contribute to the preparation of a new European standard.