Common Faults and Maintenance Methods of Street Lights

1. Overview of Street Light Management

With the increasing speed of urban development and construction, the maintenance scope of street lights is also expanding, and higher requirements are also put forward for the street light system. Once the street light fails, it will not only affect people’s daily life, but also cause frequent traffic accidents at night. There are many factors affecting the failure of street lamps, such as poor construction quality, unsatisfactory materials, unreasonable design, and substandard quality of supporting projects, etc., which may lead to the occurrence of street lamp failures. Based on this, it is necessary to effectively manage the street lights in order to solve the fault and provide convenience for the residents’ life.

2. Common Faults and Maintenance Methods

2.1 Common faults and maintenance methods when the bulb does not light up and the voltage is normal

Common faults of street lights include the following.

(1) The normal life of the bulb

During the use of the bulb, the electrode emission material it contains will gradually decrease due to normal consumption, and the impurities remaining in the arc tube will continue to be outgassed. After a relatively long period of use, the starting voltage of the light bulb will increase a lot, making the light bulb difficult to start, or even unable to start at all. When encountering such a failure, the bulb should be replaced with a new one in time.

(2) The outer glass shell is damaged or leaked

Street lights are mostly equipped with outer glass shells. Take the high pressure sodium lamp as an example, when it is damaged or leaks, the getter mirror will turn milky white. At the same time, at the niobium tubes at both ends of the arc tube, a serious oxide layer will be formed, which will affect the lighting effect of the street lamp, and a new bulb needs to be replaced.

(3) Sodium leakage from sodium lamps

When the welding seam of the sodium lamp arc tube leaks or bursts, the phenomenon of sodium leakage will occur. At this time, black sodium amalgam is deposited on the inner surface of the outer glass envelope and the outer surface of the arc tube. The occurrence of sodium leakage of sodium lamps will also affect the effect of lighting and should be replaced in time.

(4) Slow start

Slow startup is also a common street light failure. Insufficient electrode emission, insufficient output pulse amplitude, and low power supply voltage will cause the street lamp to start slowly. For the case that the output pulse amplitude is not enough, the electronic trigger needs to be replaced. For the case where the power supply voltage is too low, it is necessary to improve the power supply quality. In the case of insufficient electrode emission, the bulb needs to be replaced.

(5) Failure of the starting device

When the auxiliary starting conductor is displaced, or the heating wire in the lamp is blown, and the bimetallic sheet fails, the neon bulb is damaged, etc., the starting device in the lamp will fail. At this time, the street lamp lost its lighting function because it could not be started normally, and a new bulb had to be replaced.

(6) Lead fault

Once the lead wire inside the bulb is desoldered, or the lamp cap is loose, it may cause an open circuit or short circuit of the lead wire, resulting in the street lamp not working properly. It needs to be replaced.

(7) Intermittent self-extinguishing of the bulb

As the use time increases, the sodium contained in the bulb decreases due to normal consumption, which will lead to an increase in voltage, which will cause the bulb to turn on and off when it appears, and the bulb needs to be replaced. When the power supply voltage is in poor contact or has a large fluctuation, it will also lead to intermittent self-extinguishing faults, and the power supply quality needs to be improved. If the fault is caused by the reduced capacity of the capacitor, the capacitor should be replaced in time. When the maintenance voltage provided by the ballast is too low, so that the open circuit voltage cannot reach the required value, there will also be intermittent self-extinguishing faults, and the ballast needs to be replaced. If the cause of the failure is due to the high temperature of the working environment of the bulb, ventilation and heat dissipation should be strengthened, and the lamp should be replaced if necessary.

2.2 Common faults and maintenance methods when the bulb does not light up and the voltage is abnormal

When the bulb does not light up and the voltage in the lamp holder is not normal, the common fault types of the bulb can be divided into the following types:

(1) Fuse failure

When the porcelain plug is loose or has poor contact, it is easy to cause fuse failure. If the fault cannot be eliminated after inserting it firmly, you need to replace the fuse with a new one. At the same time, due to the overload of the line, it will also cause the fuse failure, which needs to be rewired to increase the capacity of the line itself. Improper selection of fuse specifications or excessive instantaneous starting current will lead to fuse failure, and the fuse should be replaced in time.

(2) Ballast failure

Ballast failure mainly includes three situations: open circuit, burnout, and inter-turn short circuit. When the ballast is in an open circuit state, there will be a situation where there is voltage at the input but no voltage at the output. The winding coil has poor contact or is burned, and the ballast needs to be replaced. When the ballast is burned out, the coil windings will appear burnt with a burnt smell and will also need to be replaced. The inter-turn short circuit will reduce the impedance, resulting in an increase in voltage and current, which in turn affects the life of the lamp and must be replaced.

(3) Electronic trigger failure

When the electronic trigger failure occurs in the street lamp, most of them are burned out. The shell of the lamp will be burnt black and deformed, the output pulse will be seriously affected, and it needs to be replaced in time. If the selection of the electronic trigger does not match the ballast, the amplitude of its output pulse will be lower than the standard value, which will cause the bulb to fail to start normally, and the matching electronic trigger must be replaced.

(4) Line connection failure

When a line connection failure occurs, the line connection should be checked to ensure that it meets the specified wiring standards. The connection between the live wire and the lamp head chip must pass through the ballast, and the lamp head wire should not be too long. The insulation layer of the wire is damaged, or its own withstand voltage is low, which will affect the start pulse and need to be replaced in time.

(5) Compensation capacitor fault

When the compensation capacitor fault occurs in the street lamp, it is mostly caused by the mismatch of capacitor selection. The voltage in the lamp head will be affected and become abnormal, at this time, the lamp will not light up. Compensation capacitors of the same type, capacity and specification should be replaced according to the technical requirements.

(6) The voltage is too high or too low

When the power supply voltage is higher than 242V for a long time, the service life of the lamp is shortened due to the excessive power operation time. When the power supply voltage fluctuates too much, or the input voltage is lower than 198V, it will cause difficulty in starting the bulb. The voltage should be kept stable to meet the normal starting requirements of the bulb.  

3. Conclusion

There are many types of common failures of street lamps. Therefore, for management and maintenance personnel, efforts should be made to increase practical experience. Can accurately analyze its possible causes, and take targeted maintenance methods to ensure timely troubleshooting.