1.The point of choose and buy：
With the increasingly mature technology, high-power LED light source can meet the needs of ordinary street lamps. The light efficiency of the general high pressure sodium lamp is 100LM/W, and the commonly used high-power LED is 50-60lm /W, which can reach 80LM/W with foreign LED chips. The higher the luminous efficiency, the better the energy saving effect, which is also one of the most important indicators for choosing LED street lamps. However, this is not specified in the LED standard, so it must be carefully confirmed when purchasing LED street lamps.
In order to reduce the cost, some businesses use hundreds of 0.5W low-power leds. However, the light decay of this low-power LED is very severe, falling to 80 percent with a lifetime of only 1,000 hours. Therefore, as the need for long-term use of street lamps is absolutely not allowed to use this kind of small power LED, choose high-power LED (generally refers to more than 30W), its light decay will be much better.
LED street lamp due to high technical content, complex composition and other reasons, the weight of some high-power lamp will be far more than the ordinary high-pressure sodium lamp, so the corresponding support material requirements are higher. However, some LED street lamp manufacturers have tried their best to reduce the weight of LED lamp holder, from about 30 kg for a single lamp holder to more than 10 kg, and the weight reduction has a further trend of decline.
As a semiconductor component, LED will lose its illumination significance when its chip is reduced to 30% of the initial light flux due to the influence of temperature, which means the end of its life. Theoretically, the life of high-power LED street lamp is between 30,000 and 50,000 hours, but its important premise is good heat dissipation. It is worth mentioning that domestic manufacturers have adopted the world's leading needle heat dissipation technology.
2.The cost comparison
Assume that a city has three sections of road length is 3 kilometers, 5 kilometers, 10 kilometers respectively, laying street light a lamp that every 30 m, each side one calculation, the three short walk the street lamp is respectively 202, 334, 668 total lamp, traditional street lamps will be subject to the power of 250 w high pressure sodium lamp, LED street lamp power is 50 w shall prevail.
The unit price of traditional street lamps is 1,000 yuan/lamp, and the unit price of LED street lamps is 3,000 yuan/lamp. The cost of light source needed for laying three kinds of traditional street lamps is 202* 1,000 = 202,000 yuan, 334* 1,000 = 334,000 yuan, 668* 1,000 = 668,000 yuan, and the cost of light source needed for laying three kinds of LED street lamps is 202* 3,000 = 606,000 yuan, 334* 3,000 = 1,00.2 yuan, and 668* 3,000 = 2,004,000 yuan.
Us to analyze the three sections of the cost of the two kinds of light source, laying cable length of road, 3 km road, a traditional street light trunk cable load flow I = P/U = 202 * 250/220 = 230 a, it should be 60 was cross-sectional area for copper cable, its unit price is 120 yuan/m, is the cable cost is RMB 120 * 3000 = 360000, LED street light trunk cable load flow l = P/U = 50/220 = 202 * 44 a, it should be cross-sectional area for 1 omm2 copper core cable, it should be 12 was copper core cable cross section, the unit price is 12 yuan/m, The cable cost is 12*300= 36,000 yuan, and the load flow of the traditional street light main line cable on 5km road I=P/U=333*250/220=377A, which requires the copper cable with a cross-section of 90mm2 and the unit price is 180 yuan/m, and the cable cost is 980*5000= 900,000 yuan. The load flow of the LED street light main line cable I=P/U=333*50/220=73A. The cable flow rate of the main trunk of the traditional street lamp on a 10-kilometer road I=P/U=666*250/220=680A, which requires a copper cable with a cross-section of 400m2, with a unit price of 360 yuan/m and a cable cost of 360* 10,000 = 3.6 million yuan. The load flow rate of the LED street lamp main trunk cable I=P/U=666* 50220=146A, with a cross-section of 42mm2 and a unit price of 60 yuan/m and a cost of 600,000 yuan.