Nowadays, saving energy is a major concern and the electricity area is no exception to the rule. As electrical engineers, you necessarily apply technologies or devices which aim to improve energy efficiency.
Among the front runners of these technologies stands the LED technology (Light Emitting Diode). It is indeed among the most significant progress of the last years; to the extent that LED lighting is about to become the global standard, coming after classic bulbs that soon won’t be sold by the manufacturers anymore. Notably intended for commercial and industrial buildings, and also for infrastructure (outdoor public lighting), its success lies in the fact that it produces a very efficient luminosity compared to conventional incandescent lamps.
Everybody seems to agree with the fact that LED technology is the future of lighting. However, several electrical installation professionals warned us with 2 major issues highly questioning its use.
1) Overvoltage and random tripping when switching on
When a LED luminaire is first energized, a variable current is required during the first milliseconds, and then the current stabilizes as soon as rated operating conditions are reached. Three transient fundamental events occur during the start up phase: the power supply of the luminaire, the start of the driver, and the powering of the LED module (that is to say when the light is on). Then the luminaire transitions to the steady state operating condition.
During the switching on, a peak of very significant inrush current occurs before 10 milliseconds. At that very moment circuit breakers can trip; this happens very often. Normative curves used for circuit-breaker certifications (the “standard” curves defined by NF EN 60898 and NF EN 61947-2) characterize fault currents of a duration exceeding 10 ms, and thus correspond to the circuit breakers’ tripping threshold for currents maintained for 10 ms or more. For transient currents of duration less than 10 ms, no normalized curve exists!
In other words, the LED technology can make your installations trip by nature! For circuits with more than 20 LED luminaires, the reliability during the switching on remains very uncertain; the tripping is random.
“Lately, we’ve been told that a large supermarket chain had decided to swap its 6000 classic bulbs (CFL) for 2000 LED bulbs. In theory, everything was fine until the first employee of this supermarket arrived at dawn the next day. The man says that this morning, as he intended to switch on the 2000 luminaries via the electrical panel – surprise – he had to start again and again due to circuit-breaker tripping before he managed to do it!”
2) Very sensitive to lightning surges
LED-technology luminaires contain electronic components, which make them very sensitive to surges, which can damage or even destroy the power supply drivers and LED components. This high sensitivity to lightning surges can considerably reduce the LED luminaires’ theoretical lifetime.
“To save energy, a French village chose to adopt LED technology for the outdoor public lighting, to cut-down their electricity bill. But after the installation, it turned out that using LED luminaires cost more money since these luminaires “burned out” during each stormy episode and had to be replaced.”
These feedbacks about LED technology being neither reliable, nor economical, are highly disturbing. This made us decide to raise this alert. Moreover, these issues seem to be “hidden” due to lobbying.
Here, at the Electrical Engineering Community, we decided to investigate these phenomena. As a matter of fact, we’re wondering if they are isolated cases or if, on the contrary, these issues are really observed by everybody.
That’s the reason why we invite you to answer these few questions:
Have you ever noticed one of these issues?
If you have, in which context was it?
Did you find solutions to countervail them?
Let’s share our experiences and let’s investigate together. We thank you all in advance for your answers, because helping us means helping all the electrical community and thus yourselves.
UPDATE – dec, 5th
We’ve decided to create an area to take an inventory of all the resources about these issues. And that’s not all: we also plan to share resources about the solutions to apply. These are laboratory-tested by several teams of professionals.
To receive the username and password to access to this LED resources area, simply send us an email and give details about the issues that you’ve noticed in the installations with LED luminaires. And if you never had any issue, please tell us too; every information is worth taking!
PS: Those who’ve already sent us details about the issues that they noticed will automatically receive the username and password to access to the resources area.
From Colombia. (excuse my english, i’m not a native english speaker)
With regards to the overvoltage, overcurrent and random tripping, i haven’t seen this effects. Neither i haven’t had problems with surges.
But maybe is important to request to the manufacturers more technical information related to the inrush current and withstand voltage of its products.
In other hand, i have had problems with electromagnetic compatibility EMC between LED Drivers and suceptible equipments in medical installations.
The LED Drivers were producing radiated and conducted interference in an echograph connected through an dedicated UPS. Parcial solutions has been achieved with the use of metallic conduit and total shielding of the feeder of the equipment, but it hasn’t been enough. I am trying to specify an emc filer for the conducted radiation.
I have measured power, rated current and Harmonic content of different Led lamp ( between 8 W and 25 W) The surprise was the spread of THDI, from 25% to 150 %.
The THDI should be request to manufactrurer as guaranteed data. I`m sure this has a deep impact in EMC and EMI interference due to the different drivers used.
I’ve read Jason’s commented. Neither did I have any problems with surges or overvoltage and random tripping. What I did find that some LED drivers are interfering with two radio signals. When the Led lights are off, you have clear and perfect radio signals and coms, but as so as you switched on the site office LED Lights the radio signals get scrambled with weak coms.
All my office’s PC monitors are changed with new ones. These new ones have the same problem you mentioned. Radio comms interference. When monitor alone is switched off the comms are functioning fine. Radio Comms getting scrambled when monitor is ON. So the problem might be with the LED backlight of monitor.
I think it depends on how it was made , because LED as of this time is like a cup cake.some manufacturer produce more even if it is out of standard and selling it by smuggle.For me i bought it to the legit manufacturer and am been using it almost 5 years
We have a couple of LED’s which illuminates an external commercial Signboard. In the middle of the night, the dedicated 20 Amp single pole breaker trips all the way.The actual recorded current is 12 amps ( logo + name signboard ) the only successful solution is separation of circuits for Logo and Name connected to separate circuit breaker.
Nice, you managed to find a solution ! And were you able to separate the circuits easily ? I had the same problem and I’m still looking for a conveninent solution…!
Have been using LED Lights since long. Have not experienced the tripping.
Awaiting commissioning of one ongoing project where LED has been used heavily to comply Sustainability norms of the project.
Let us see.
i have been using LED but i can confess that i do not know whether it has some benefit like this……….
I bought 1 LED bulb 5 W a months ago then one time i noticed @ 6:00 pm (peak hour) when i switch it on the bulb is keep on flickering i switch it off after 2 min. when i turn it back the same thing happened.The next day it back to normal.
In some electrical installations of customers, I have measured high level of flickers, Pst and Plt.
When I checked what were the main loads, the majority of them have installed LED Lamps.
I have measured level over 2.6 . This level of flickers I have seen in steel plants where they have EAF (high voltage electric arc furnaces).
I am not sure about the correlation, but always I see the presence of harmonics and flickers.
As everybody knows, LED lamps, will inject harmonics but looks to me that will affect the voltage in the form of flickers.
the only way to use led is like the Christmas tree bulbs (serial connection to divide the voltage)
i want some parts for repairing the circuit
For one of my clients , we installed LED lamps to cut down energy consumption, but we couldn’t find remarkable saving in energy even after 0ne year of installation.