Views:0 Author:Site Editor Publish Time: 2021-09-10 Origin:Site
One of the major threats facing outdoor LED lighting fixtures today is transient surge events in AC power lines, especially lightning surges, which can cause damage to the fixture. Today, any LED fixture contains a DC-DC power converter, AN LED driver, and a heat sink for thermal control and optical components to optimize light quality. Lightning surge can cause failure of internal components or circuits of LED lamps directly connected to ac input power (such as 120/220VAC mains), resulting in damage to LED lamps due to short circuit and overload conditions.
In recent years, there have been a number of LED lighting enterprises, almost all of them are struggling with the cost, whether one SPD can solve all the surge problems: it is impossible. Lightning protection is a knowledge, is a science, is a whole complete industry, want a medicine to cure all diseases that is wishful thinking.
Academic and theoretical basis such as: electromagnetic field theory, arc theory, electrical contact theory, electrical principle, power supply and distribution, communication theory, signal transmission and processing, advanced mathematics and so on, the main standards are IEC61643, GB18802, UL1449 and so on. Different standards, how can they be mixed? There's no comparison.
1. Material level;
2. Component level;
3. SPD Finished product level;
4. Level of external lightning protection engineering interface.
Lightning protection industry development so far, more than 50 years of history, this is a complete, mature industry. We have been seeking to integrate the lightning protection industry with the LED lighting industry, and finally bring reliable protection solutions to the end customers. However, the "cost" of each company's senior management is a death sentence for reasonable lightning protection design.
An overvoltage transient surge may occur on the AC power line due to the open and close action of nearby electrical equipment. Nearby lightning strikes can also create transient surges in AC power lines, especially in outdoor environments.
At the moment of a lightning strike, the level of electrostatic discharge from the clouds to the ground usually reaches millions of volts. A lightning strike from miles away can induce an induced voltage of up to thousands of volts in current-carrying copper wires, such as underground cables for street lamps. These indirect shocks are characterized by specific waveforms that typically contain large amounts of energy in excess of 1000A2s.
About 70 percent of lightning strikes occur over land in the tropics, where most thunderstorms occur. African countries have experienced the worst and longest lightning strikes in recorded history. The most frequent lightning strikes occur near Kifka, a small village in the mountains of eastern DRC, at an altitude of about 975 meters. On average, there are 158 lightning strikes per square kilometer per year in the region. A large area around the site has also been badly affected, as inductive surges from lightning strikes increase the chances of damage to outdoor LED lighting.
Central and South America, Africa, South and Southeast Asia also have similar lightning frequencies to the United States, according to A NASA study of lightning frequencies around the world. Therefore, in the United States, we recommend that the equivalent surge immunity be between 5kA and 10kA. For other areas with less lightning frequency, such as Europe, east Asia and Australia, a low surge immunity of 3kA to 5kA can be considered.