Four Ways of Lightning Strike for LED Street Lights

There are mainly four types of lightning strikes:

1. Lightning strikes at distant lightning strikes the line or the extremely high voltage generated by electromagnetic induction, and is transmitted from the outdoor power line and communication line to the electrical equipment inside the building.

2, direct lightning strike Lei Yun contains great energy, peak voltage up to 5000kV lightning current into the ground, with great destructive power. It will have the following three effects:

(1) A huge, rich current flows down the ground in a few microseconds, rapidly picking up the ground potential, causing a counterattack and endangering the safety of people and equipment.

(2) Lightning currents generate strong electromagnetic waves, and extremely high pulse voltages are induced on power lines and signal lines.

(3) Lightning currents flow through electrical equipment and generate extremely high heat, causing fire or explosion.

3. Frequent discharges between the induced thundercloud layers generate strong electromagnetic waves that cause common mode and differential mode interference, affecting the operation of electrical equipment.

4. Inductive and capacitive loads in the switching overvoltage supply system are turned on or off, shorted in the ground, short circuited in the power supply line, etc., and can generate high voltage pulses on the power line. The pulse voltage can reach 3 to 5 times the normal voltage. , can seriously damage the device. Damage effects are similar to lightning strikes.

So how do we prevent lightning accidents? After research, we found that the following methods are the most effective ways to prevent street lighting from being destroyed by lightning:

1, set lightning protection zone In addition to the current LED street lighting power supply equipment, it will also set up some communications equipment to control the street light switch and brightness, these devices and power supply need to be placed in the lightning protection zone, the protection zone is directly shielded by the shell. The electromagnetic field here is much weaker.

2, lightning equipotential connection to completely eliminate the destruction caused by lightning potential difference, power lines, signal lines, metal pipes, etc. must be used to protect the voltage potential of equipotential bonding, the interface of the various inner protection zone also Local equipotential bonding is carried out, and the local equipotential bonding sites are connected to each other and finally to the main equipotential bonding site.

3, external lightning protection combined with internal lightning protection The general exterior of the LED street lamp is a conductor material, itself is equivalent to a lightning rod, in the design must be installed under the lead and ground network, these systems constitute an external lightning protection system. The system can avoid the fire and personal safety accident caused by direct lightning strikes on LED street lamps. The internal lightning protection system means that the interior of the street lamp is protected by means of grounding, voltage protection and other means. The system can prevent inductive lightning and other forms of over-voltage intrusion, resulting in power destruction, which is not guaranteed by external lightning protection systems. The two are mutually reinforcing and complement each other. The internal lightning protection system must be connected to an external lightning protection system or an overvoltage protection device on many devices such as the enclosure, cables to and from the protection zone, metal pipes, etc., and must be connected equipotentially.

4, high-quality protection equipment - lightning protection module and surge protection module role is to protect the system in the shortest time (nanoseconds) connected to the system of equal potential, so that the device port equal potential. At the same time, the huge pulse energy generated by the lightning strike in the circuit is released to the ground via the short-circuit line, which reduces the potential difference of each interface terminal of the device, thereby protecting the device.

The LED street light power module must not only be designed in accordance with the above requirements, but must also undergo rigorous inspection procedures:

1. Control devices with constant voltage output function or constant current output function or both shall be tested with the safety standard of GB 19510.12/IEC61347-2-13.

2. For the control device that only has the function of controlling the logic change of the LED brightness, darkness, flashing, color, etc., the GB 19510.12/IEC61347-2-11 safety standard inspection should be used.

3. If a control device has both the above-mentioned functions, it shall be tested in accordance with the safety standard of GB 19510.12/IEC 61347-2-13.

Practice has proved that after scientific design and strict inspection, not only can the LED street light system be protected from lightning damage, but also the common mode and differential mode interference of the lightning power supply device can be eliminated.