The lighting of the high pole lights in the west area of Hongqiao Airport adopts the half night mode. The microcomputer sends the switch signal to control the high pole lamp, and turns off some lamps on each high pole lamp in the middle of the night to save energy. High pressure sodium lamps on each high pole lamp are 1000W, at least 7 lamps, and some have 9 or 12 lamps. The consumption of ballast, capacitor and trigger in each lamp circuit can be ignored, as shown in Figure 3. The lighting time of each base high pole lamp is from 6pm to 6am the next day, a total of 12h, and it consumes a lot of electricity every evening. Turn off the lights on the circuit in the middle of the night after 1:00 a.m., that is, only three lights are on each base pole lamp. Rough calculation, assuming that each base of all high pole lamps is (7+9+12)/3=9, then 6 lamps are only on for 7h and off for 5h each night, so (6/9) × (5/12) ≈ 0.28, it can be concluded that nearly 28% of electric energy is saved, which will be a considerable figure.

In the second half of the night, only the lights of the all night circuit are turned on. After several high pole lamps are selected on site to test their brightness, the data in the following table are obtained. According to the above data, it can be calculated that the average value of light intensity is 21.3lx, and the uniformity (average value/minimum value) is 1.72. According to the provisions of the fourth edition of the airport in Annex 14 of Civil Aviation, the light intensity of the high pole lamp on the apron is not less than 20lx, and the uniformity is not more than 4. Therefore, the energy-saving scheme using midnight light mode effectively meets the regulations and requirements.