Through the case analysis of the key points of the application of LED street lamp

At present, with the continuous development of LED lighting technology, mainly due to the increase of its power, efficiency, cost, more and more are used in various lighting projects. LED not only in the field of decorative lighting, also has a place in the field of functional lighting. Such as signal lights, car taillights, waterproof explosion-proof flashlight, including part of the indoor lighting and road lighting. LED is a solid light source, with its long life, Gao Guangxiao, color and a light radiation function, can work under low voltage in safety, but also continuous switch flash, can easily achieve 0~100% dimming function and other advantages, become the development trend of the new generation light source.

For nearly a period of time, under the slogan of energy conservation and emission reduction, all over the country have launched LED road lighting project. However, in the field of functional requirements of high, LED met a lot of resistance, it is clear that in the current development of LED street lamp to expose some of its shortcomings. It is not difficult to see around the LED road lighting projects are mostly independent implementation, good and bad, there is a trial and error, repeated waste situation. If we can achieve information sharing within the industry, and the introduction of a number of practical and tentative standards, LED street lamps will certainly play a role in promoting the healthy and rapid development. In the following, the author takes a LED street lamp as an example, combined with the characteristics of LED itself, the advantages and disadvantages of the LED street lamp in the development process to make a judgment, hoping to play a role in attracting jade.

Analysis of the basic advantages of LED

As a new light source, LED is in a stage of rapid development, the current high power white light LED has 100lm/W; through the research and the luminescent mechanism, it can calculate the radiation efficiency of up to 350lm/W LED, also has the very big development space. One of the features of the LED is a directional light, in the practical application as far as possible to make light of the light directly at LED respectively by each region face, with the lamp reflector assisted with light, precise light distribution to meet a variety of needs, so the LED street lamp light distribution design precision in place is the key to replace the traditional lamp the.

LED no obvious failure mechanism, the theoretical life of up to 100 thousand hours. In the application of floodlights, LED is usually agreed that the output of the luminous flux decay to 70% of the initial value of the end of life, according to the existing LED life expectancy of 50 thousand hours. Can greatly reduce maintenance work, save operating costs.

As a semiconductor light source, LED respond quickly, can work in the continuous switch off state, easy to achieve 0~100% dimming, can be integrated with the control system, according to the need to adjust the light output.

case analysis

08 years in mid June, the road on both sides of a non isolated Shanghai long 3.1KM with the installation of 313 LED lights.

Source power:

Main road: 27*5W=135W,

Non motorized vehicle: 16*5W=80W,

Light distribution: the three optical design: 1 LED chip, the direction of output light is strong, there is a good optical design; 2, each LED installation location and the light direction set separately, this is the distribution with the luminaire reflector surface; 3, the use of the reflector as the auxiliary means the final.

Lamp post:

Pole height: 10M; (light source to road surface)

Pick arm: 1m; (double pick)

Pitch: 28m; (symmetrical arrangement)

Road width: 32m;

Measured data after 4 months:

Average illumination: 18lux

Uniformity: 0.4

Lane uniformity: 0.35

Actual results are shown in figure 1.

Figure 1 installed on a road in Shanghai LED street lamp

1 Comprehensive Evaluation

Compared with the traditional sodium lamp and metal halide lamp, LED has obvious advantages in addition to saving considerable power.

1) although the traditional light source has a higher luminous efficiency: sodium lamp 110lm/W, metal halide lamp 80lm/W. However, when the light source is used in the road lamps, only 40% of the light is directly exposed to the road surface, and the other is projected by the lamp reflector. And this kind of lamp reflector efficiency is only 50%~60%, lamp efficiency is generally only 70%. Reflector design is difficult, can not really meet the needs of light distribution, the general direction of illumination in the direct illumination is too large, and the two lights at the intersection of light is too small.

In contrast, LED street lamp, 3 light distribution design so that most of the light is directly projected onto the road, the overall lighting efficiency of 50lm/W.

2) LED light source output white light color up to 65, color temperature: 5000K~6000K, compared to sodium lamp, light color is more natural. According to the theory of "intermediate vision", the white LED has a higher equivalent visual effect, which is about 40% in the middle visual condition, while the equivalent optical efficiency of the "yellow light" high pressure sodium lamp is reduced by about 30%. Although the middle vision theory based on human senses, there is no exact standard is still in dispute, but the high color LED drivers and pedestrians will undoubtedly help to identify targets, provide better traffic conditions on the road under the same brightness.

3) sodium lamp and metal halide lamp are high pressure gas discharge lamp, after starting out for some time, the heat start time is up to 5 ~ 8 minutes. The LED lamp can work under the condition of continuous switch.

4) LED lamp can realize 0~100% continuous dimming, can adjust the light output according to the ambient light and traffic condition, and reduce the unnecessary power consumption while guaranteeing the lighting quality. The traditional light sodium lamp and metal halide lamp can only achieve the dimming control in a small range, and the application is inevitably limited by the minimum working voltage.

5) LED lamps