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The importance of surge protection of LED Outdoor Lighting

May 30, 2019

The importance of surge protection of LED Outdoor Lighting


Lightning strikes are electrostatic discharges that typically carry millions of volts from the clouds to the ground or to another cloud. During transmission, lightning generates electromagnetic fields in the air, inducing thousands of volts (surges) to the power line and generating induced currents that travel hundreds of miles away. These indirect attacks typically occur on outdoor exposed wires, such as street lights. Equipment such as traffic lights and base stations emit surges. The surge protection module directly faces the surge interference from the power line at the front end of the circuit. It transfers or absorbs surge energy, minimizing the threat of surges to other working circuits, such as AC/DC power units in LED lighting fixtures.


For outdoor LED lighting drive power, the use environment determines that lightning protection is an important indicator to measure its performance. Therefore, lightning protection design must be considered for outdoor LED power supply. Taking the lightning protection circuit of the AC input of the power source well known by engineers as an example, the lightning protection of the AC input of the power supply is mainly caused by absorbing the transient energy brought by the lightning strike or discharging the energy to the earth through a predetermined path. Avoid impact on the back end of the power supply.


For LED street lights, lightning generates an induced surge on the power line. This surge of energy creates a surge on the wire, that is, a surge wave. The surge is transmitted through such induction. The outside world has a surge. The wave will create a tip on the sine wave in the 220V transmission line. When the tip enters the street light, it will damage the LED street lamp circuit.


Street lamps have been around for many years. Why do we need to find lightning protection for street lamps? In fact, the high-pressure sodium lamps and traditional mercury lamps used in the past are designed with high-voltage bulbs, which have the effect of lightning protection. In recent years, LED lights have become more and more popular. LED lights require a small supply voltage. Usually, the power supply is used to convert AC power to DC power. This makes the LED street lamp itself have no lightning protection, so surge protection module needs to be designed for street lamps.


Reference:US three-level lightning protection standard


In the US National Standards released in 2015, three levels of lightning protection standards have been introduced. The reason is that the three grades are due to the fact that the tribes of the East and West tribes in the United States are quite different. The high mines can reach 30 to 40 times, while the low mines have only one or two times. Therefore, three levels are standard. 6kV, 10kV and 20kV. This is also a flexibility for luminaire manufacturers and local governments. Local governments can decide to use the corresponding standards according to actual conditions.