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Analysis of LED Street Light Replacing High Pressure Sodium Lamp In Road Lighting

Apr 29, 2019

Analysis of LED Street Light Replacing High Pressure Sodium Lamp In Road Lighting


With the rapid development of the global economy and increasing energy demand, energy conservation and emission reduction have become the primary concern of the world, especially, energy conservation is an important part of energy conservation and emission reduction. This article compares the current situation of urban road lighting and compares LEDs. The technical parameters of street lamps and high-pressure sodium lamps have been analyzed and calculated. It is concluded that the use of LED lamps in road lighting can save a lot of energy, and can indirectly reduce the emission of a large number of harmful gases, improve the environmental quality, and achieve the goal of energy saving and emission reduction.

At present, the light sources of urban road lighting mainly include traditional high-pressure sodium lamps and fluorescent lamps. Among them, high-pressure sodium lamps are widely used in road lighting because of their high luminous efficiency and strong fog penetration ability. Combined with the current road lighting design features, road lighting with high-pressure sodium lamps has the following shortcomings:

1. The lighting fixture is directly illuminating on the ground, and the illuminance is high. It can reach more than 401 lux in some secondary roads. Obviously, this illuminance belongs to over-illumination, resulting in a large amount of electric energy wasted. At the same time, at the intersection of two adjacent lamps, the illuminance only reaches about 40% of the direct illumination direction, which cannot effectively meet the lighting demand.

2. The efficiency of the high-pressure sodium lamp emitter is only about 50-60%, which means that in the illumination, nearly 30-40% of the light is illuminated inside the lamp, the overall efficiency is only 60%, there is a serious Waste phenomenon.

3. Theoretically, the life of high-pressure sodium lamps can reach 15,000 hours, but due to grid voltage fluctuations and operating environment, the service life is far from the theoretical life, and the damage rate of lamps per year exceeds 60%.

Compared with traditional high-pressure sodium lamps, LED street lamps have the following advantages:

1. As a semiconductor component, in theory, the effective life of an LED lamp can reach 50,000 hours, which is far higher than the 15,000 hours of high-pressure sodium lamps.

2. Compared with high-pressure sodium lamps, the color rendering index of LED lamps can reach 80 or more, which is quite close to natural light. Under such illumination, the recognition function of the human eye can be effectively utilized to ensure road safety.

3. When the street light is turned on, the high-pressure sodium lamp needs a preheating process, and the light needs a certain time from dark to bright, which not only causes waste of electric energy, but also affects the effective development of intelligent control. In contrast, LED lights can achieve optimal illumination at the moment of opening, and there is no so-called start-up time, so that good intelligent energy-saving control can be achieved.

4. From the perspective of the illuminating mechanism, the high-pressure sodium lamp uses mercury vapor luminescence. If the light source is discarded, if it cannot be effectively treated, it will inevitably cause corresponding environmental pollution. The LED lamp adopts solid-state lighting, and there is no harmful substance to the human body. It is an environmental friendly light source.

5. From the aspect of optical system analysis, the illumination of high-pressure sodium lamp belongs to omnidirectional illumination. More than 50% of the light needs to be reflected by the reflector to illuminate the ground. In the process of reflection, part of the light will be lost, which will affect its utilization. The LED lamp belongs to one-way illumination, and the light is intended to be directly directed to the illumination, so the utilization rate is relatively high.

6. In high-pressure sodium lamps, the light distribution curve needs to be determined by a reflector, so there are great limitations; in the LED lamp, a distributed light source is adopted, and the effective design of each electric light source can show the ideal state of the light source of the lamp, realize reasonable adjustment of the light distribution curve, control the distribution of light, and keep the illumination relatively uniform within the effective illumination range of the lamp.

7. At the same time, the LED lamp has a more complete automatic control system, which can adjust the brightness of the lamp according to different time periods and lighting conditions, which can achieve good energy saving effect.

In summary, compared with the use of high-pressure sodium lamps for road lighting, LED street lights are more energy-efficient and environmentally friendly.