The following link is for the ABB Ufes system. Available both for medium and low voltage systems.

Any thoughts on this kind of system compared to "normal" arc guard systems?


http://www.abb.com/product/db0003db004279/05d1e893194566e9c1257799003303d7.aspx

Two things. First, it is a slick way to get around some issues. The major advantage of photosensors is that you get the photosensor speed (usually 2-3 ms) plus the opening time of the breaker and you can retrofit it easily. It's also WAY cheaper than the other system you referred to.

Referring to your earlier comments, 50-60 ms is not that bad. It depends on the available fault current. RMU's, network protectors, and the like, tend to have really high available fault currents, which tend to require very fast clearing. Otherwise normally the major problem with a lot of faults is that since it's an arcing fault, the time it takes for the protection relay to detect the arcing fault can be very long, especially without impedance grounding where it is fairly straightforward to detect ground faults. At best you can sometimes use differential protection. BUT if you can reduce the typical 100-500 ms opening time due to delays in fault detection down to 5-15 ms, that's a huge improvement.

Second, Ufes is not the only one. Schneider sells "Arc terminator" which is similar. There are others on the market as well.

There are two designs. One causes a dead short. The other opens a breaker that normally bypasses a set of resistors inline with the main bus. The first one completely shuts down an arc flash at the expense of forcing the main breaker to open under dead fault conditions and subjects the equipment to a full AIC fault. The second significantly reduces the arc flash down to a controlled level but does not necessarily shut it down completely until the main breaker opens.

Either way, the "create a bolted fault" design relies on the ease of closing onto an energized line. The "add resistant" design relies on the ease of clearing an arc when a lower impedance path is available which is commonly used on high voltage transmission lines to control transients during switching.

GE was supossed to have some kind of device to it is called ARC VAULT
it was creating a 3 phase arc in a vault that would extinguish the external arc (an impedence thing)
the fault would stay in the vault until main breaker open
it was suppose to bring almost every design to level 0, since it would operate in a couple of millisec

One more thing...this is not the ONLY way to interrupt a circuit. There are ways to interrupt that are significantly faster than SF6 or vacuum interrupters. In fact even air breakers are faster with the lower voltages and sizes.

One method is a solid state breaker. It is exactly what it sounds like...the SCR's or IGBT's are opened using forced commutation to be able to interrupt in just a couple milliseconds. Granted these things are E-X-P-E-N-S-I-V-E and limited to special uses. S&C sells one version on the market.

Second method is a little slower, called a smart fuse. In this design, a standard fuse link with a fairly high short circuit rating is installed. A low voltage capacitive trip device sits on the side. On command from a trip relay, the capacitor couples to the fuse and delivers a high current, low voltage current and blows out the fuse. Obviously the fuse links have to be replaced after every circuit trip but you get 1/4 cycle (4 ms) trip speed, far faster than Ufes, and if it's a Ufes design, there wouldn't be a need to fire very often in the first place.

Overall as an equipment manufacturer, I'd probably consider going after the fuse link version because of simplicity, cost, and size, as an alternative to Ufes.

i have heard of fuse limiter on 600V breaker like DSL breaker ...mostly use to lower max fault current that the breaker as to open

but never heard about those fuse....if you have a web link or something would be interested to see that

I had a look at the ABB document "Catalog UFES" dated 2012.
The "Primary Switching Elements" (PSE) have ratings up to 40kV, 40kA.
Each PSE is sacrificial, one-time use only, like a fuse. That limits testability. Like an airbag in a vehicle, user has to trust it will work when needed.
Looks like the electrical gear being protected has to be designed around the PSE devices. OK for new systems, more difficult for existing systems.
The document I reviewed does not list any agency ratings, for N. America or others; maybe I need to look elsewhere.

I had a look at the ABB document "Catalog UFES" dated 2012.
The "Primary Switching Elements" (PSE) have ratings up to 40kV, 40kA.
Each PSE is sacrificial, one-time use only, like a fuse. That limits testability. Like an airbag in a vehicle, user has to trust it will work when needed.
Looks like the electrical gear being protected has to be designed around the PSE devices. OK for new systems, more difficult for existing systems.
The document I reviewed does not list any agency ratings, for N. America or others; maybe I need to look elsewhere.

S&C Fault Fiter fuses have this feature. Right now their implementation is a single phase device only with a "limited" programmable relay. I believe you can get custom relay settings done though. No one I know of yet has extended the basic concept and idea into what it could be. Even S&C hasn't taken the obvious step of allowing fault fiter fuses to be "linked" into a 3-phase device.

Hi. I work for ABB as Medium Voltage Service business development manager - protection and controls. The UFES can be installed on older switchgear as a retrofit option and an excellent way to mitigate arc faults. One of the comments above mentioned 2-3 ms plus the clearing time of the breaker. The relay reacts in that time, but the primary switching elements are triggered in less than 4ms, grounding the circuit they are connected to. The energy is channeled immediately to ground, therefore the arc is quenched by removing the source. The switching elements can sustain the full shorting current while the upstream breaker clears. The UFES system can be used in conjunction with the REA optical sensing relay to utilize current and light sensing on LV switchboards and MCC's, and trigger the UFES grounding either the LV bus or the primary of a transformer, which removes all the delay of fusing on the primary of a transformer.

To clarify some confusion below the ABB UFES indeed will clear a fault in 4ms. The UFES is not relying on the Breaker to open in order to clear the fault. UFES works by activating a Micro Gas Generator located in the PSE module which creates a path to ground in 4ms or less.

If anyone needs any clarification or technical data you can contact me directly at information below.



Kenneth VanDyken
National OEM Business Development Manager