T O P

Total shutdown today to install arc flash protection

Total shutdown today to install arc flash protection

poldim

What kv is this?


roloiii

132/22 kV, doing at the 22kV side


jesus_burger

What switchgear manufacture is this? That's some MASSIVE 22kV breaker trucks.


VTEE

Must be rated for 35. Those things are huge


overheadpressbrah

I've seen 25kV breakers of this construction


VTEE

Right, but it’s probably a 35kV bottle and breaker, just nameplated at 22.


pictocube

What country is this?


Frankfallujah16

What’s the arc flash protection?


roloiii

It's a scheme where it instantly trips the switchgears whenever there is an arc flash inside to reduce (not prevent) damage to the components. If not implemented, it will cause severe damage to the parts or even explosion.


JohnProof

Are y'all putting in up optical pickup relays? I've only seen those in a few sites. I've always wondered how they stack up against a really tightly set differential or ground fault scheme?


roloiii

Yea it's probably that. It's added just recently to a few sites in my area I think this scheme is a bit different from the usual ones, since it depends on light presence and current threshold


beckerc73

So SEL then? Definitely helps prevent misops from pointing with a laser ;)


sChlickers

Could be other manufacturer like abb or schneider Using light/current scheme is only necessary when there are possiblities that direct high intensity light (such as camera flash) hit the sensor. Implementing such scheme could also require the addition of additional CTs or Rogowski coils, which could be somewhat quite expansive


beckerc73

Hmmm, if I ran into a case where there were no CTs to use I'd address that first - still want to have O/C backup! A laser has actually worked better for me than some flashes on picking up one of the sensors. Sure, a flashlight won't do it, but the coherent light from the laser seems to more easily enter a "bare fiber" loop sensor.


sChlickers

Arc flash detection schemes and overcurrent protection are not necessarely backup of one another. Of course there must be an O/C scheme in place. What I was explaining is that for some reasons It could be very impractical and/or simply Impossible to use the existing CTs or sensors, so it could be required to add these equipment to implement the current /light scheme. This could end up to ben quite an expensive upgrade, considering that it MAY not be required to prevent unlikely trip due to light sensitivity of light oy scheme. It is definitely a case of “evaluate the needs” and “don’t overdesign”. Don’t forget also that other options are available to reduce the energy levels such as implementing maintenance mode (force an a lower-current instantaneous OC protection (at the expense of protection coordination) during switching/rack in/rack out operations.) An ultra fast earth switch (UFES) is also a great option. These though are also light triggered.


beckerc73

You're right, the engineering answer is "it depends" and there's always some example. I definitely like "always in" arc flash protection - but have put in what you've mentioned with a few names (RELT for "Reduced energy let-through" was the weirdest name in my opinion, but very descriptive. Have only messed with a couple 57's ("high speed grounding switch") - and it wasn't light triggered - adds to that "it depends" I guess!


beckerc73

I know in SEL that the processing/operate time is faster than the normal overcurrent/instantaneous because an unfiltered current is used. They also provide the option to bypass some processing time and route directly to a high-speed output.


VTEE

First time I saw that I thought the engineer was on crack, but it’s right in the manual. Nifty trick


beckerc73

Looping in some fiber sensors?


roloiii

Yup


beckerc73

Noice


ale_mongrel

Ok. new guy here. I actually havent started yet, Im taking a week off before I start, but Im going to be working in substations soon, I curious as to how this works. I read Those are devices designed to open the mains in the event of an arc. So are the sensors in the nose? and fiber is run between them all so they are daisy chained together and ties in at the main to open the breaker? If so why fiber? Would say a low voltage 3 conductor cable suffice? Im genuinley curious.


JohnProof

You're looking at the breakers themselves, and each phase conductor is concealed inside that red insulating plastic. The fiber is installed in the cubicle where each breaker installs, that way if there's ever a breakdown in those red insulators and a flash occurs, the fiber optic will transmit the light to a protective relay with an optical sensor. The relay then isolates the energy sources going to that breaker cubicle.


ale_mongrel

Huh. No shit. Thats cool. Thank you.


ElprofesorAleman

What is shut down? Is this a private company? a utility sub?


Fuzzy_Chom

Nice visual open(s)! 👍


magnetohydroid

weird boner