In recent years, China's street lamp construction has achieved rapid development, road lighting quality has been continuously improved, and high-intensity gas discharge lamps have been widely used to improve China's investment environment, promote rapid economic development, facilitate people's lives, beautify cities and serve as an outward direction. The construction of a modern city has played a big role, but with the substantial increase in energy consumption, especially in recent years, the energy price has increased significantly, making electricity consumption a burden. Take Xi'an as an example. The street lamp electricity fee is 6 million yuan, and it has risen to 18 million yuan in 2003. Therefore, it is necessary to strengthen technical improvements to slow down the trend of rising energy consumption. In the era of promoting green lighting all over the world, the energy saving of street lamps is bound to become a trend.
Second, the theoretical basis of street lamp power saving
Since the power consumed by the gas discharge lamp is related to its input voltage, taking the sodium lamp as an example, see Figure c. When the voltage is reduced by 10%, the current is reduced by 10%, while the power is reduced by 25% and the luminous flux is reduced by 30%. . Since normal illuminance needs have been taken into account when designing road illumination, energy consumption should not be reduced by reducing illumination. However, considering that the traffic flow of the vehicle is greatly reduced in the latter half of the night, the power supply voltage is increased due to the reduction of the power load. Therefore, it is also feasible to reduce the luminous flux of the light source by lowering the power supply voltage, assuming that the power supply voltage is in the latter half of the night. When the voltage is increased by 10%, and then the power supply voltage is reduced by 10% to operate, the luminous flux is reduced to 70% of the rated value, and the power consumption can be reduced by 50%.
The following is a set of measured data, see the table below, using the energy-saving magnetic ballast of Xi'an Radio 2 and Nanjing Sanle, 250 watt sodium lamp. It can be seen from the table that the input power is reduced by 140.6 watts when the voltage drops from 242 volts to 198 volts. The rated power value is reduced by 53% compared to 220 volts.
Since the reform and opening up, China's power generation equipment has been continuously completed and connected to the grid for power generation. The transmission and distribution network has been upgraded, which has improved the voltage at the end of the original grid. However, the voltage of the grid is generally high, especially at night. High, such as some units in a certain area of ​​220 volts at night to 254 volts, the general unit is close to 240 volts, when the power equipment is running above the rated voltage of the equipment, it will lead to excessive heat, shorten the life, the experiment proves incandescent The power supply voltage is increased by 5%, the life is reduced by 47%, the fluorescent lamp voltage is increased by 10%, the life is reduced by 15%, and a large number of electrical equipment (such as motors, transformers, contactors, electromagnets, etc.) have iron core electrical, An increase in voltage causes an increase in iron loss and copper loss. Because the electrical equipment operates above the rated voltage and current, the core loss is proportional to the square of the total voltage, and the copper loss is proportional to the square of the current, thus creating a large energy waste. It also reduces the average life of the device.
By adjusting the supply voltage and reducing unnecessary losses, not only can the purpose of power saving be achieved, but also the terminal equipment can be protected and the average service life of the equipment can be extended.
In the current streetlight power supply system, since the power supply voltage cannot be adjusted, the light source often cannot work in a suitable state. The life of the current light source has been very long. For example, the life of the sodium lamp of GE has reached 28,000 hours, and the domestic production has reached 18,000 hours. However, the actual use is often not achieved, the main reason is that its working state does not reach the ideal state, according to the current power transformer voltage detection in Xi'an. 80% of the power supply voltage is high, especially in the latter half of the night, the transformer output voltage is up to 250 volts. The long-term operation of the light source and this environment will greatly reduce its service life and waste a lot of energy. Therefore, the method of adjusting the power supply voltage can not only save energy, but also prolong the life of the light source, which is a better energy-saving method.
Third, the status quo of China's street lighting energy saving
There are many ways to improve road lighting efficiency, such as the use of high-efficiency light sources, lamps, etc. At present, a large number of high-efficiency high-pressure sodium lamps are used in road lighting, and the efficiency of lamps is also increasing. Below we only discuss street lamps. The method of saving electricity and its influencing factors.
At present, there are two main ways to save energy at the power supply end. One is to use a midnight light, and the other is to use a voltage regulation method.
The midnight light is energy-saving by turning off a part of the street light in the middle of the night. It has the characteristics of being simple and easy to operate. The disadvantage is that the road lighting is uneven, and the problem that the voltage is high in the middle of the night and affects the life of the light source cannot be solved.
The method of reducing the supply voltage can not only save energy, but also prolong the life of the light source. It is a better energy-saving method, and is currently in trial operation in the country.
1. The commonly used step-down mode: the current AC voltage regulation methods mainly include contact voltage regulator, induction voltage regulator, transfer voltage regulator, magnetic voltage regulator, compensation voltage regulator, and on-load voltage regulation power. Transformers, thyristor regulators and other different ways.
2. Comparison of commonly used step-down methods: For the energy-saving retrofit of existing lighting systems, it is generally economical and practical to install energy-saving equipment. At present, there are many lighting energy-saving equipments sold in China, among which lighting control and control devices account for the largest proportion. From the working principle, it is roughly divided into three categories.