1 question raised
With the development of social and economic construction, the construction level of urban road lighting has become an important symbol of the speed and level of urban development. The quality of lighting projects not only affects the safety of vehicles and pedestrians, but also the energy conservation and environmental protection goals. At present, the energy consumption of road lighting in China is very serious. The main problems are the over-standard lighting system design, the backward lighting control method, the wrong lighting energy-saving concept, and the single lighting energy-saving measures. This is obviously related to the concept of “constructing a conservation-oriented society†proposed by the Chinese government. Related information. On March 5, 2012, Premier Wen Jiabao pointed out to the 11th National People's Congress a government work report that China's energy conservation and emission reduction targets were not completed in 2011, which means that energy consumption will be completed in the next four years of the 12th Five-Year Plan. The task of reducing carbon emissions is even more arduous, and the situation of energy conservation and emission reduction in China is very serious. As mentioned above, urban road lighting in China is a major energy consumer. As a large number of urban roads are put into use, the energy saving of road lighting becomes increasingly urgent and important. How to rationally design according to the nature of the city and the road grade, and to save energy on the basis of meeting the functional lighting requirements of urban roads has become a very important research topic.
2 Urban road lighting engineering energy saving method
There are many ways to save energy in urban road lighting projects. In combination, it is better to find the optimal design scheme, choose the light source reasonably, set the reactive power compensation, choose the reasonable control method, and adopt the electronic ballast. .
2.1 Seeking the best design
In the design, the corresponding illuminance and power density standard values ​​should be selected according to the nature of the city, the function and grade of the road, and the characteristics of the city, the grade of the road, the reflectivity of the road surface and the traffic conditions should be clarified before design. The key factors affecting the lighting design are the average brightness of the road surface, the uniformity of the road surface brightness distribution, the technical indicators of the illuminator and the degree of glare suppression, and the inducement of the road illuminator arrangement. These factors directly affect the quality of the design. Finally, under the premise of ensuring functional lighting requirements, determine the optimal lighting distance, the most reasonable light source and lighting, power supply route, control system, etc., in order to maximize energy saving and investment, and reduce operating and maintenance costs.
2.2 Reasonable choice of light source
The energy-saving effect of the light source mainly depends on the light efficiency and light attenuation index of the light source. The color rendering, service life and starting characteristics should be considered comprehensively. The light source with high light efficiency and long life should be used as much as possible. At present, road functional lighting sources mainly include metal halide lamps, incandescent lamps, high pressure sodium lamps, compact fluorescent lamps, and the like. Under the same electric power, the high-pressure sodium light energy is about 4O higher than that of the metal halide lamp, and the fogging performance of the sodium lamp is better; according to the road illumination requirements of the same illumination standard, the power consumption of the metal halide lamp source is much higher than that of the high-pressure sodium lamp, so the high voltage Sodium lamps are widely used in urban road lighting projects. With the development of technology, LED light source technology with low power consumption as the main feature has become increasingly mature, and LED light sources have been greatly promoted in many large and medium cities. LED light source is characterized by long life, high efficiency, energy saving, safety and environmental protection. Compared with the high-pressure sodium lamp, the power consumption of the LED light source is 18.7 of the high-pressure sodium lamp, and the new high-power LED street lamp can save 8O of electric energy, and the high-pressure sodium lamp generally used in the street lamp can be replaced in the lighting effect.
The solar street light uses sunlight as energy. During the day, the solar panel charges the battery. At night, the battery supplies power to the light source. Because it has no influence from the mains supply, it does not need to be buried or overhead, safe, energy-saving and pollution-free, as long as the sun is sufficient. It can be widely used because of its features such as local installation. Therefore, in the case of conditions such as sufficient sunlight, solar street lamps should be used as lighting sources.
2.3 Setting reactive power compensation
Most of the urban road lighting sources are gas discharge lamps, the power factor is very low, generally 0.38 ~ O.6_3], in addition to the supply of active power, the power supply still needs to supply reactive power. This power can cause voltage drop (inductive reactance) or voltage rise (capacitive reactance) and Joule (resistance heat) loss in the power grid, but can not make effective work. It can be seen that the flow of reactive power in the transmission line and the transformer will increase the active power loss and the reactive power loss and the voltage drop; since the reactance value of the transformer and the high voltage overhead line is far greater than the resistance value, the reactive power loss The loss is greater than the active power, and the main factor causing the voltage drop is the flow of reactive power. Therefore, it is imperative to reduce the loss of the power supply transformer and the transmission line, improve the power supply efficiency, and improve the power supply environment.