Any bad experences with arc flash relays 2

[cranky108]

Looking at reducing arc flash hazard's on older switchgear. What problems has anyone had with arc flash relays?

Is lightning a problem?
Dosen't the overcurrent relay solve that?

Do you leave the flash relay turned on all the time or only when someone is in the gear?

 

[Zogzog]

You are going to need to be more specific, there are many different type made by many different OEM's.

 

[dpc]

cranky,

If you're talking about the ABB light-sensing relay, it is normally supervised by an overcurrent element to reduce false tripping. Flashes of light are certainly a problem. In the demonstration I saw, a camera flash was used to trigger the relay.

 

[wbd]

If you look at the published relay actuation time of 2 ms and then add the breaker operate time and any signal propagation time, you find that this is most likely faster than any overcurrent relay. This is faster since it actuates on a light flash and a current level. The current would be set at a level above normal FLA.

I have not experienced or heard of any issues with the relay.

 

[rovineye]

It is left on all the time. There may be unusual circumstances when it would be dis-abled, but none that come to mind. Maybe if taking photos with a flash around energized switchgear and there was no associated over current sensor, such as near a port (window) designed for infrared inspections.

There are some others that work off of atmosphere sensing as well (TIDs I think they are called). They sniff for fumes indicative of a fault as well as looking for the flash and maybe even sensing pressure. These work very well, but not sure if they are available commercially, and are expensive.

 

[cranky108]

I had proposed the arc flash relay to our substation guys, and they came back with that they had heard there was a lot of problems with them being sensitive to lightning.

1. If they would seal the switchgear from dirt intrusion then lightning should not be a problem (my thinking).

2. They could be blowing smoke up my butt because they don't want anything new.

3. There really could be problems that the manufactures don't want to admit (Which I want to know about).

The reason I am interested in these is in several older switchgears we don't have CT's for differentials, and I want to reduce the arc flash energys by adding fast tripping on the main bus.

 

[Eleceng01]

cranky108,

Reading your posting reminded me of a conference paper & presentation at the Western Protective Relaying Conference (WPRC) in 2007. The paper was titled "Arc Flash Hazard Mitigation Applied in Switchgear with Air Magnetic Circuit Breakers."

What I took away from the presentation was that it was the routing of the fiber is very critical. I got the impression that if it wasn't routed correctly it could/would misoperate. I was involved with an arc flash mitigation project for 5kV switchgear at that time, so it scratched that as an option for me.

Hope this was helpful.

 

[cranky108]

Eleceng01, actually that is insightful. The question then comes to me how would someone determine the best routing.

I would assume that since I am interested in protecting people I would want it in locations where people and arcs are closest in proxminity.

 

[dpc]

I was at the presentation as well. I guess my take was a little different. But there is a concern regarding field installation of the sensing fiber. I would be more concerned about failure to detect the arc based on improper location rather than false tripping. The fault current supervision should eliminate nearly all nuisance tripping.

 

[wbd]

In one of our industrial plants, we had high AF due to the switchgear being connected directly to the transformer secondaries. The ABB relay was the best solution to reducing the AFH. ABB was hired to route the fiber in the cubicles.

As dpc noted, the fault current supervision will eliminate false tripping due to light flashes from a camera or lightning.

 

[Eleceng01]

dpc, I agree with you and it sounds like we both took the same thing from the presentation.

My personal definition though is that a "failure to detect the arc based on improper location rather than false tripping" is still a misoperation.

wbd, that might be the key here, to have ABB route the fiber . Have you had any actual arc flash events or only the commissioning testing? I am interested to see if it works as advertised. If it does, it is a great solution.

 

[wbd]

We have been fortunate enough not to have had any arc flash events. My understanding is that these relays were in use in Europe for a number of years prior to the states, so there is some operational history.

Any one from Europe have any experience or comments on the REA relays from ABB?

 

[Skogsgurra]

Yes, plenty. Saw them first some 25 years ago. Only problem that I know about is that people sometimes use cameras with flash. All doors to electrical rooms where there is an arc flash relay therefore has a sign saying that no flashes are allowed.

I do not see why routing should be a problem. Light enters only at the termination. The fibre is clad an not sensitive to stray light. Lightning? That problem (if it ever existed) was taken care about long time ago.

We usually do not test with a camera flash, but with a cigarette lighter. The sparks produced from flint/wheel are good test signals.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[stevenal]

I liked the other European system presented at the WPRC. I wonder if they know what Vamp (the company name) means in English.
The high speed crow bar diverting the energy along with the wearable arc flash detector seems like the ultimate in incident energy reduction.

 

[dpc]

Gunnar,

There are apparently two types of detectors these days. One is a continuous fiber loop that is light-sensitive along its entire length. At least that is my understanding.

Dave

 

[Skogsgurra]

Like a leaking cable then? But opposite.

Got to refresh my knowledge. It was some time ago I used those things. That new one - is it also ABB?

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[dpc]

Yes - ABB. They have been making a big push on this relay in the US.

 

[cranky108]

I think ABB will have an another relay manufacturer in the US market soon. The relay was being shown at WPRC in 2008.

 

[slavag]

Hi.
We haven't expirience with this type of relays.
But according to our data arc flash relay is very popular in lot of companies.
As Dave saied, very important point is OC detection in additional to flash detection, it's avoid unwanted trip in case of flash of camera ot something else.
REA of ABB in the market ferw years. It was dedicated product. In the newer relays ABB add this option (additional card) in the feeder protection, for example REF610.
Possible build few loops of fiber optic.
VAMP is also Finland company, as ABB Finland ( Stromberg in past) are in the Vaasa city.
Few Russian companies provided arc flash relays with few type of operation. In the Russian companies today is standard used arc flash relays.

As I knoe Siemens use another solution, I check my data and will attach it.
Best Regards.
Slava

 

[stwalk]

I just had a sales person from SEL come in last week to discuss their Arc Flash relay.

I ask about camera flashes and he responded saying that the light threshold that the relay picks up is well above the flash from a camera. Guess testing it is the only way to find out for sure.