North Carolina power substations taken out by gunfire 16

[FacEngrPE]

https://www.foxnews.com/us/north-carolina-sheriff-says-intentional-vandalism-substations-caused-power-outages-40k-customers[/URL]]A North Carolina sheriff and power company official said "intentional vandalism" at substations has caused outages for about 40,000 customers expected to last longer than 24 hours

NC county announces curfew as nearly 40,000 customers remain without power after 2 substations damaged by gunfire; Tina Burnside, By Nicole Grether, Gloria Pazmino and Tina Burnside, CNN Updated 6:12 PM EST, Sun December 4, 2022

Current outages link

https://www.readync.gov/stay-informed/power-outages

and

https://outagemaps.duke-energy.com/#/current-outages/ncsc

Moore County Sheriff's Office Dec 4

 

[dik]

Oh goodie... more carbon dioxide...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[cranky108]

So what is the difference between 60Hz and 50Hz? I believe they can build a compressor motor that can use either. at 60Hz it can run at 3600 RPM, and at 50Hz it can run at 3000 RPM.

 

[JohnRBaker]

Yes, when I was working as a machine designer, the vendor we bought our motors from, when the equipment was going to be shipped to a 50Hz country, they would supply us with a replacement nameplate with the specs for the 50Hz service. The motors were built such that the safety factor was sufficient so that it could run at either frequency. Of course, we had to keep that in mind when we were specifying the other relevant drive components, such as pulley's, sprockets, gearboxes, etc, so that it was going to run at the proper speed when it was installed. And of course we had to keep that in mind when they tested the machines on the shop floor before shipment since we didn't have a way of providing 50Hz power in the factory (we were located in Saginaw, Michigan, although we were a subsidiary of a British company).

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Alistair_Heaton]

It will be to do with mass flow rate and heat generation.

Modern units will be inverter variable speed units with variable expansion valves. T won't really care what the supply frequency is.

The bulk of the containers units will be simple fixed orifice on off regulated units.

 

[Alistair_Heaton]

John would I be right in thinking that 60hz on 50hz there wouldn't really be much of an issue apart from a drop in performance. But a 50hz designed and spec'd components might had issues?

They might have put a different expansion valve in as well between the two models.

A designed in UK and spent it's life on UK boats moving food about put on a gom drilling rig definitely doesn't survive the experience.

 

[JohnRBaker]

Since these were American designed and manufacture motors, I would assume that they were intended for 60Hz service, but the safety factor was such that running them in a de-rated manner, i.e. 50Hz instead of 60Hz, was not an issue.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Alistair_Heaton]

I wasn't questioning your product. More getting my head round the reason why the UK one failed.

Off the top of my head the post compressor pressure would be higher for a fixed expansion valve and resulting temp. Torque on shaft would also be higher.

 

[TugboatEng]

I would guess that a lot of assumptions were made during the failure analysis which is typical of the offshore environment. Even severely overheated motors don't tend to catch fire on the outside. Fires more often start from control side failures such as a welded contact or mechanical failures like hot bearings.

 

[byrdj]

4pm news briefing announced that area GOLF courses will be open tomorrow.
State of Emergancy and Curfew ends at 05:00EST
Duke anticipates having all service restored tonight

 

[FacEngrPE]

Just like applying a motor to a VFD, as long as the input Volts / Hz ratio is observed, a motor will spin and be electrically OK.
Available motor torque being a function of current, remains constant (subject to available cooling).
Available power is lower at 50 HZ than 60 HZ due to torque being constant and speed lower.

If Volts per Hertz ratio is not maintained, magnetizing current will go out of bounds, and damage will likely result.

We did this with a 50 Hz Scoda MG set used with a large machine tool spindle drive, with no resulting maintenance problems.

 

[cranky108]

Actually, if the HP demand is small, a universal motor could be used. I had an electric lawn mower, years ago, that used a universal motor, but was installed with a rectifier.
Easy to use and light. And when the rectifier failed, I just happened to have a like and kind to replace it. Not that I planned that, but I had one.
Besides, induction motors don't run at system frequency anyway. They run a little slower.
The only issue is three phase motors are sensitive rotation direction.
Single phase and VFD controlled are not.

 

[FacEngrPE]

Some newspaper coverage
Repair Crews Working Around the Clock to Restore Service By JAYMIE BAXLEY || jaymie@thepilot.com Dec 6, 2022

Investigation Presses On As Substation Repair Work Continues BY JONATHAN BYM, JAYMIE BAXLEY, ANA RISANO and MARY KATE MURPHY || Staff Writers Dec 6, 2022 Updated Dec 6, 2022

Tuesday Update: Timeline for Those Without Power Improves Staff Report Dec 6, 2022 Updated Dec 6, 2022

Power Restored to Over 22,800, With Parts of Downtown Southern Pines, Hospital Back Online By JAYMIE BAXLEY || jaymie@thepilot.com Dec 7, 2022 Updated Dec 7, 2022

Thursday Update: Power Returns, Curfew Lifted as Investigation Continues Staff Report Dec 7, 2022 Updated 1 hr ago

Looks like it's just cleanup and law enforcement now. This restoration was impressively fast.

Universal motors have their place, but large ones like the traction motors on the GG1 locomotive are rarely produced now. Each GG1 sported 12 ea 385 HP motors that were applied at 25 HZ.

https://www.steamlocomotive.com/GG1/quill.php

 

[davefitz]

One way to reduce such acts is to install monitorng cameras and devices that trace cell phone pings, so as to help catch the persons responsible. Already there are millions of "doorbell cameras" employed just to catch porch pirates, the same can be had for infrastructure.

It sometimes seems that the timing of such "terrorist events" is about 1 week prior to a congressional vote on terror legislation- it might be useful to see if such a vote was timed a week after that event.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

 

[cranky108]

A company I worked for, years ago, would have shooting often. They would put a light on the edge of the substation.
Shooters at night would shoot the light, then could not see anything. That was the end of the shooting.

 

[Alistair_Heaton]

this is being reported this side of the pond

https://uk.news.yahoo.com/fbi-north-carolina-authorities-issue-212719756.html

 

[RedSnake]

This restoration was impressively fast.

It the same in Ukraine it always surprises me and it is impressive that they manage to get most of the grid and infrastructure fixed and working again in three to five days when the Russians bomb things out and then after a couple of days they have to start all over again.
Guess that's why they like to show this animation.

https://t.me/operativnoZSU/61808

This classic will be repeated from time to time

Zaporizhzhia OVA showed how the smoke did not settle down after the rocket hit, and the relevant services started the recovery work.
At night, the S-300 rocket "defeated" the road between two villages of Zaporizhzhya district, and by dusk the road was restored.
We work for a joint victory!

And then they need to make rolling blackouts to keep the whole grid in order on start up and after shelling and destruction.

https://t.me/operativnoZSU/61811

At Ukrenergo, they showed the chief specialist who is responsible for emergency power outages.

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[JohnRBaker]

There was another attack on a North Carolina power distribution station three weeks prior to this latest incident:

Another North Carolina power substation was disabled before the Moore County attack

https://www.newsobserver.com/news/local/article269713541.html

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Palletjack]

 There was another attack on a North Carolina power distribution station three weeks prior to this latest incident:  Another North Carolina power substation was disabled before the Moore County attack  [URL unfurl="true"]https://www.newsobserver.com/news/local/article269...[/URL]]

Yes. But that area had an extensive loop system in place already. That station isn't back in service yet.

We worked from Saturday night until Wednesday on this in Moore County, with some of us working 40 hours straight.

 

[1503-44]

4 in Washington St.

https://youtu.be/22_DG8jNAoQ

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[davidbeach]

So, now, anybody willing to accept that the North Carolina events were just part of an ongoing rash of stuff?

I’ll see your silver lining and raise you two black clouds. - Protection Operations