Харківський національний університет міського господарства імені О.М. Бекетова, Україна ПОТОЧНИЙ СТАН І ПОТЕНЦІАЛ ПІДВИЩЕННЯ ЕНЕРГОЕФЕКТИВНОСТІ СИСТЕМ ОСВІТЛЕННЯ МІСТА ХАРКОВА В статті наведений стислий аналіз стану енергетичного комплексу країни та структура споживання електроенергії. Проведено аналіз балансу мережі зовнішнього освітлення м Харкова. Розглянуто можливість впровадження енергоефективних технологій у систему міського освітлення з метою скорочення витрат на електричну енергію.

Human beings perceive information from the environment by using their sense organs. Vision is believed to provide the most information. There are three categories of vision: scotopic, mesopic, and photopic vision. The activity of two types of light-sensitive receptors in the eye, cones and rods, is different for each category. Cones and rods have a unique ability to adapt to different levels of illumination. Adaptation is the ability of the human eye to adapt to changing lighting conditions. Thanks to this mechanism, the human visual system has the ability to operate in a very wide range of pupil illuminations, that is, at different adaptive levels. At very low adaptive levels, only the rods are active, and the vision is called scotopic. As adaptive levels increase, starting at 0.005 cd/m2, the rods become less active, meanwhile the cones become active, and then the vision is called mesopic. At adaptive levels above 5 cd/m2, only cones are active, and the vision becomes photopic. Cones and rods have different spectral sensitivities: rods are more sensitive to short wavelengths, while cones are most sensitive within the visible spectral range. Cones are concentrated mainly in the part of the retina of the eye that is used for direct (on-line) vision, while rods are localized only in the areas used for peripheral vision. As a result, in case of mesopic vision, the peripheral vision becomes better with light sources that have a relatively large component of short wavelengths. The same is true for the subjective perception of brightness. At low adaptation levels, more rods become active, and thus these benefits are greater at low illumination levels. Since photometric units are based on photopic vision, these advantages are not obvious. Thus, the correction factors should be determined according to the spectrum of light sources, which is characterized by the S/P ratio, and the illumination levels of road lighting. The International Commission on Illumination has prepared a standard (CIE 115:2010 Lighting of roads for motor and pedestrian traffic). The main goals of road lighting are to ensure visual performance, visual comfort and to keep drivers alert.

Color is not a physical properly of object, but rather a human perception enabled by light. Never­theless the color of light sources is described by the industry primarily in terms of two metrics, correlated color temperature (CCT) and color rendering index (CRI), that are only indirectly related to human perception. CCT is intended to characterize the appearance of the illumination generated by source, and CRI is intended to characterize the appearance of objects illuminated be the source. There two color metrics developed nearly of half-century ago, are increasingly being challenged because new source are being developed with increasingly exotic spectral power distribution. The new color metric applicable to the color appearance of the light emitted by at light source and quantified by the CCT and D. The chromaticity is one of the critical parameters for light sources for general lighting and normally specified with chromaticity coordinates CIE (x, y) or (', '). However these two numbers do not provide the color information intuitively. For practical purposes, collated color temperature (CCT) is commonly used to provide the chromaticity information of general illumination source CCT, however, provides only one dimension of the chromaticity and there is ano­ther dimension, which is the position of chromati­city with respect to Plancian locus. For this purpose «D» or similar terms as distance from Plancian locus have been need used in some part at the industry but these had not beer officially defined is any standard. Color rendering is general term for describing the ability of a light source to provide color information to human observer when objects are illuminated by that source like CCT color rendering index (CRI), the most accepted measure of color rendering. CRI was developed, through the system of colori­metry, simply to be an indication of how «natural» or «undistorted» the light source makes the color of objects appear when illuminated by the source when used as the sole measure of color rendering for a light source, CRI simply cannot meet expectations. With the advent of SSL, these limitations have become more widely recognized. It was proposed a two-metric system combi­ning CRI, a measure of color consistency with respect to a reference source, with gamut area index (GAI), a measure of color saturation. When used to ga­ther, the two metrics appear to optimize the color appeara­nce of natural objects like fruits and vegetable enhancing their vividness with making them appear unnatural. CCT is shown in commercial instruments but D is often avai­lable. D needs to be calculated using the method of triangular solution: Create a table CCT is distance di to Plancian locus on () coordinate; Find the closest point in the table; Solve the triangle for the neighboring 2 points. Gamut area of light source is commonly calculated as the area of the polygon defined by the chromaticities in CIE 1977 (', ') color space of the light CIE TCSs. Gamut area of EES is sealed to 100 and defined as gamut area index. The gamut area of any other light source is scaled accondingle.

High-quality street lighting improves visual perception of the road and provides for a significant decrease in the number of road accidents. It has been established that the total number of accidents can be reduced by 30% for national roads and by 45% for especially hazard areas (e.g., at intersections). Doubling of the average luminance of the road surface significantly reduces the number of accidents in the dark and twilight. Sufficient street lighting contributes to: reducing electricity consumption; decreasing operating costs; improving the environmental situation; promoting business, tourism and investment activity; decreasing the number of criminal offenses. The analysis of recent research and publications helped choose the best European practices which can be used to improve the outdoor lighting in Ukraine. The street lighting network is continuously growing and being modernized. Different types of light sources are being used in the network to illuminate the city. Today, high-pressure lamps (HPS) are leading. They are increasingly replaced by LED light sources. Not a small share is accounted for by metal-halide lamps. The smallest number of light sources in the street lighting system, high-pressure mercury and compact fluorescent lamps (CFLs). To increase the efficiency of the street lighting system and reduce energy consumption for its operation, measures for its reconstruction and modernization are required. For this purpose, it is necessary to address the following problems: high level of obsolescence and physical wear and tear of system elements; inefficient use and high losses of electricity at the stages of transportation and consumption, due to the use of obsolete and worn-out equipment; suboptimal distribution of the utility capacity, which leads to ineffective use of the existing lighting system; low efficiency of the street lighting control system, due to the lack of electric meters and remote monitoring and control of the street lighting. Introduction of energy-saving types of light sources is one of the ways to modernize the existing street lighting system. It is necessary to replace old lighting fixtures, which have already exhausted their life span, by new energy-saving light sources (replace CFLs by LEDs), use automatic control systems. All this in turn will help reduce energy costs by 60%. To improve energy efficiency of the street lighting system, it is also recommended to carryout the replacement of electromagnetic ballasts by electronic ones. The employment of electronic ballasts, e.g., in case of using HPS 250 lamps, allows to save approximately 255 kWh/year. Considering that the price per kW of electric energy is UAH 2.68, one luminaire helps save the amount of UAH 683.4 per year.