Jump to content

Texas Sucks Part III


jsharr

Recommended Posts

27 minutes ago, Kirby said:

Cute story about a delivery driver whose car got stuck making a delivery during the early part of the storm.  The couple to whom she was delivering groceries invited her in and are still letting her stay with them since her apartment didn't have power. Love when the good in people shows during bad times.  As Mr Rogers's mother said "look for the helpers"

https://abc7ny.com/weather/strangers-shelter-stranded-delivery-driver-for-days-during-winter-storms/10353603/

Owl say it before someone else does “Was she hot?”

  • Heart 1
  • Haha 1
Link to comment
Share on other sites

1 hour ago, Longjohn said:

My cat sometimes sits at the door looking out the window. I open the door a little bit and ask him he wants to go out for a bit to cool off. He backs away from the door and says “No way, I’m a house cat now”.

Oreo is smart!

  • Heart 2
Link to comment
Share on other sites

 @jsharr  I remember reading about how close TX was to a total blackout last week.   Now it appears it was MUCH closer to happening than I ever expected.     

https://www.nbcdfw.com/investigations/ercot-texas-was-4-minutes-and-37-seconds-away-from-a-blackout-that-could-have-lasted-months/2562592/

I sure hope the 'reliability standards' get updated to include COLD weather.   Too bad ERCOT didn't learn from the 2011 outages.  

  • Heart 1
Link to comment
Share on other sites

Quote

Texas was less than five minutes away from a blackout that might have crippled the power system for weeks or months.

Can one of the electric engineers or similarly aware individuals here explain what would have happened within 5 minutes that would have caused a sustained blackout if measures (which I assume was cutting power to homes?) hadn’t happened? I understand supply wasn’t meeting demand, but what would have happed within 5 minutes, and why wouldn’t that be undone quickly, once more energy production could be re-established?

Link to comment
Share on other sites

1 hour ago, Prophet Zacharia said:

Can one of the electric engineers or similarly aware individuals here explain what would have happened within 5 minutes that would have caused a sustained blackout if measures (which I assume was cutting power to homes?) hadn’t happened? I understand supply wasn’t meeting demand, but what would have happed within 5 minutes, and why wouldn’t that be undone quickly, once more energy production could be re-established?

Good question!  I hate when the news makes statements like that with no explanation of why.

 

Link to comment
Share on other sites

The worst case scenario: Demand for power outstrips the supply of power generation available on the grid, causing equipment to catch fire, substations to blow and power lines to go down.

If the grid had gone totally offline, the physical damage to power infrastructure from overwhelming the grid could have taken months to repair, said Bernadette Johnson, senior vice president of power and renewables at Enverus, an oil and gas software and information company headquartered in Austin.

 

https://www.texastribune.org/2021/02/18/texas-power-outages-ercot/

Link to comment
Share on other sites

51 minutes ago, Prophet Zacharia said:

What would cause the fires and explosions? Lack or electric current going through the lines???

I am thinking transformers blowing from over capacity like what happened on the east coast in '03?  You'd think they'd have circuit breakers though to protect infrastructure like that though.

Link to comment
Share on other sites

Here is an interesting video, one of many. It shows the amount of power blasting through the air in these common controlled operations. Imagine what it would be like in a major failure mode where all the circuit breakers on the grid were popping almost simultaneously in an automated effort to offset excess demand. Around here, a single circuit breaker failure in a power distribution node disables that node for potentially weeks. They have to truck in and install replacement parts. 

 

Link to comment
Share on other sites

2 hours ago, Prophet Zacharia said:

What would cause the fires and explosions? Lack or electric current going through the lines???

Attempts by the equipment that wasn't separated from the grid fast enough to power the whole load.  I'm going to assume that current would go up at each source to feed the load till some limit was exceeded and then fire, flame and maybe even locusts.

The loads don't go away but the sources must be separated from the grid before it's too late.  As sources fail, there is a cascade of shutdowns till the grid goes dark.  If the sources are not cut off in time and are damaged then it will be a much longer and more incomplete process to bring parts of the grid back up later.

  • Heart 1
  • Awesome 1
Link to comment
Share on other sites

55 minutes ago, maddmaxx said:

Attempts by the equipment that wasn't separated from the grid fast enough to power the whole load.  I'm going to assume that current would go up at each source to feed the load till some limit was exceeded and then fire, flame and maybe even locusts.

The loads don't go away but the sources must be separated from the grid before it's too late.  As sources fail, there is a cascade of shutdowns till the grid goes dark.  If the sources are not cut off in time and are damaged then it will be a much longer and more incomplete process to bring parts of the grid back up later.

That's possible... 

An electric grid MUST always balance electric load with electric generation.  If that goes out of balance quickly (seconds or less) then there automatic relays in place to protect the grid. 

 There are under frequency relays.  The grid here uses 60 cycle power distribution.    When there is too much load for the generators the frequency will start to drop.  If the frequency drops too much like down to 58 Hz then the relay will operate and a breaker will open, to reduce the electric load.   This all happens rather fast. 

 Texas had LOTS of generation tripping off line.  That's VERY bad for stability of a grid.

Think of a line of dominos up on end ready to fall over...

Domino GIFs - Get the best GIF on GIPHY

You loose A LOT generation, and under frequency relays start working.  The first domino falls....    Then the next generator trips off, and some more relays will trip.

The idea of rolling blackouts...  You shed the load BEFORE the relays start automatically tripping off load.   Then you black out another area for a while, restoring power to the first area.  A controlled load reduction...  so generation and electric load are equal.   That didn't work to good.   There was WAY too much generation that tripped.

If they didn't get the electric load reduced quickly... the relays would do thier thing and protect the system.

The problem is... most breakers would work as designed and open.  Some may not. (a very small percentage)   That would be bad.   Then stuff could indeed fail and blow up under overload conditions.

This is something you NEVER want to do.   Murphy's law... some critical location could fail and that would take months to repair.

 

 

 

 

  • Heart 3
Link to comment
Share on other sites

31 minutes ago, donkpow said:

That would be exciting to see, right?

You don't want to be ANYWHERE near equipment that blows up.   I've seen stuff blow up 3 times.   When porcelain insulators explode... it's like a bomb went off and that is very sharp shrapnel flying everywhere.  

The video above is not stuff blowing up.  That's high voltage switching in a substation, possibly opening/closing under load.  I never saw arch like that during all the switching I saw over the many years.  

  • Heart 1
Link to comment
Share on other sites

5 hours ago, Bikeguy said:

You don't want to be ANYWHERE near equipment that blows up.   I've seen stuff blow up 3 times.   When porcelain insulators explode... it's like a bomb went off and that is very sharp shrapnel flying everywhere.  

The video above is not stuff blowing up.  That's high voltage switching in a substation, possibly opening/closing under load.  I never saw arch like that during all the switching I saw over the many years.  

I don’t think you heard my story of an electrician seeing God when he opened a main breaker under load for a large industrial plant. Amazingly he was unhurt. He was a little wifty after that though, but he also was before. 

  • Heart 1
Link to comment
Share on other sites

Bikeguy's absolutely right about the protection relays. If you're so inclined here's a list of the relay functions used to protect electrical equipment:

https://systemsengr.com/substation-control-panel/ansi-ieee-standard-device-numbers/

He's also absolutely right about how failed electrical equipment can seriously injure or kill a person in a fraction of a heartbeat. 

Note that the spokesperson said 'crippled the power system for weeks or months' they really didn't give a definition of 'crippled'.  I could see major difficulties for weeks, but I suspect the 'months' was referring to some of the lesser sub-systems of the grid that would go unrepaired because of low priority.

In any electrical system the protective relays, fuses, and breakers strike a careful balance.  Go for full on safety to protect the equipment, and the system isn't durable enough to handle short transients (i.e. a lightning strike) without dropping significant portions whenever the smallest disturbance occurs.  Go for high tolerance, and equipment will cook itself waiting for the protection to kick in.   There's no perfect balance, only compromise that's selected using experience and judgment.

Big transformers, for example, have a lead time of about 6 months from purchase order to delivery.  That's doesn't include the time up front to write the spec, place the purchase order, review the pre-production drawings and the time after delivery to install and commission the transformer.  If the transformer was damaged, then other equipment around it may have been too - and now you're into a full project replacing a lot of gear.

One of the most difficult situations in power production is called a 'black start' - when a power plant has to essentially start itself by its own bootstraps.  Plants have generator(s) on site to do this, but it's not an easy process.  It's even harder when equipment has been tripped off line and it's cooled down - which it definitely would have done.  And the generators are often diesel units which don't start easily in cold weather unless they've been winterized and we know how that story went.

Then when the plant is back up, it's not just willy-nilly close the big Frankenstein Switch and re-energize the grid.  Do that and you're back to a black start.  Crews have to go and lop off sections of the transmission and distribution system by opening switches.  This isolates failed sections and contains the electrical system to a size and load the generation plant can manage.  It takes time to do this, and even more time under snow/ice conditions.  A power company could spend several days doing this, which can cascade by delaying other operations until this is done.  That's assuming they find no damage to critical sections that have to be repaired first.

So let's say you get the plant back up and get a smaller section of the grid operating.  To get more grid operational you need more generation.  Assuming the line between the plants are still in good repair, then every plant that gets connected to the grid to provide more capacity has to be synchronized to the frequency already on the system.  This is usually done automatically, but it still needs to be done.  If it's done badly because of faulty equipment the new generator can act (without going into great detail) like a huge short circuit on the system. 

In the end the system operator has to bring back up a compromised system that's designed to operate in a careful balance, under conditions with a lot of unknowns, operating with production and stability margins that would be narrower than normal.  NO operator is going to proceed with a 'drive fast and take chances' approach to restoring power because it's easily back to square one.

That's a big generalization of a lot of factors, but I think it represents a snapshot of why a grid could be down for weeks with sections being out for months, when events take a electrical power grid completely off line.

 

  • Heart 1
Link to comment
Share on other sites

57 minutes ago, Thaddeus Kosciuszko said:

Bikeguy's absolutely right about the protection relays. If you're so inclined here's a list of the relay functions used to protect electrical equipment:

https://systemsengr.com/substation-control-panel/ansi-ieee-standard-device-numbers/

He's also absolutely right about how failed electrical equipment can seriously injure or kill a person in a fraction of a heartbeat. 

Note that the spokesperson said 'crippled the power system for weeks or months' they really didn't give a definition of 'crippled'.  I could see major difficulties for weeks, but I suspect the 'months' was referring to some of the lesser sub-systems of the grid that would go unrepaired because of low priority.

In any electrical system the protective relays, fuses, and breakers strike a careful balance.  Go for full on safety to protect the equipment, and the system isn't durable enough to handle short transients (i.e. a lightning strike) without dropping significant portions whenever the smallest disturbance occurs.  Go for high tolerance, and equipment will cook itself waiting for the protection to kick in.   There's no perfect balance, only compromise that's selected using experience and judgment.

Big transformers, for example, have a lead time of about 6 months from purchase order to delivery.  That's doesn't include the time up front to write the spec, place the purchase order, review the pre-production drawings and the time after delivery to install and commission the transformer.  If the transformer was damaged, then other equipment around it may have been too - and now you're into a full project replacing a lot of gear.

One of the most difficult situations in power production is called a 'black start' - when a power plant has to essentially start itself by its own bootstraps.  Plants have generator(s) on site to do this, but it's not an easy process.  It's even harder when equipment has been tripped off line and it's cooled down - which it definitely would have done.  And the generators are often diesel units which don't start easily in cold weather unless they've been winterized and we know how that story went.

Then when the plant is back up, it's not just willy-nilly close the big Frankenstein Switch and re-energize the grid.  Do that and you're back to a black start.  Crews have to go and lop off sections of the transmission and distribution system by opening switches.  This isolates failed sections and contains the electrical system to a size and load the generation plant can manage.  It takes time to do this, and even more time under snow/ice conditions.  A power company could spend several days doing this, which can cascade by delaying other operations until this is done.  That's assuming they find no damage to critical sections that have to be repaired first.

So let's say you get the plant back up and get a smaller section of the grid operating.  To get more grid operational you need more generation.  Assuming the line between the plants are still in good repair, then every plant that gets connected to the grid to provide more capacity has to be synchronized to the frequency already on the system.  This is usually done automatically, but it still needs to be done.  If it's done badly because of faulty equipment the new generator can act (without going into great detail) like a huge short circuit on the system. 

In the end the system operator has to bring back up a compromised system that's designed to operate in a careful balance, under conditions with a lot of unknowns, operating with production and stability margins that would be narrower than normal.  NO operator is going to proceed with a 'drive fast and take chances' approach to restoring power because it's easily back to square one.

That's a big generalization of a lot of factors, but I think it represents a snapshot of why a grid could be down for weeks with sections being out for months, when events take a electrical power grid completely off line.

Yeah...  it gets very complicated rather fast.  @Thaddeus Kosciuszko  Obviously you have knowledge of high voltage distribution. 

I remember one meeting....  I was sitting next to the project manager for the installation of about 150MW of cogen at a 85 MW chemical plant. (they were planning on selling to the market too)  My relay guys started talking to there relay guys..   The project manager looks at me... 'Lets go for coffee'.   My mechanical engineering degree helped... but those guys could have been talking German for all we knew.    I paid attention and learned a lot over 40 years.   One thing... the guys in relay protection can have a job for life.. soooo much tech skills needed for their jobs. 

I just hope the reliability criterial used in TX gets updated for cold weather.   The fallout from this will be interesting to say the least.

 

 

  • Heart 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...