wind power

[petersonra]

A while ago there was some debate about the cost and long term viablity of wind power. My little brother is an economist who specializes in dealing with the electric utility industry. So I sent an email off to him and asked him what he thought. This is what he said.

Well that's a loaded question! It depends on what you mean. I did a study for XXXXXXXXXXX in 2007 and claimed that less than 20kW is about $2400-$3000/kW, for the larger units you might get that down to between $1000/kW and $2000/kW. The variable cost are not zero, however. They can be as much as 2 cents a kWh. Also, as you know, these resources are not dispatchable by the system operator, given the intermittent nature of the resources the cost could be anywhere from 9 cents/kWh to 23 cents/kWh. Ah but there is more, the system as it is designed now is a "dumb" system. That is, there is really no way to use load as a resource (e.g., VARs) Without that ability, most system operators claim that they cannot handle more than about 15-20 percent wind on the system (without expensive upgrades to existing traditional generation or the building of new generation to back up the wind generation). In fact TX had a near collapse of the system in 2007 when the wind just stopped blowing for about an hour! Now you can see why the issue is so murky.

wow. power that requires near 100% backup capacity, and costs 2 to 5 times what other sources cost. what a bargain.

BTW, he is a liberal democrat.

[LarryFine]

BTW, he is a liberal democrat.
"Is there another kind?" ~ Jack Nicholson as Col. Nathan R Jessup in A Few Good Men

[hardworkingstiff]

Bob, what does lil brother say is the future of electricity?

[dereckbc]

Well I have been designing solar power PV systems for a few years now for the telecom sector for remote cell sites, moderate a alternative energy forum, and live in TX the largest renewable energy producer state in the US (wind)

Asides from the cost being unjustifiable, the real problem with solar and wind is for every watt of renewable energy you put online, you have to build a watt standing by in a moments notice.

This is not theory but hard lessons learned from experience. For example on Feb 27, 2008 in TX the winds failed when a cold front moved through the area causing a huge blackout in various parts of the state and in a little city called Dallas leaving some very large customers red faced with substantial losses in production. It took controllers several hours to bring conventional boilers up to temperature to replace the shortage in power production.

I hope this does not take a wrong turn, but what really irritates me we have the technology and fuel supply right now to solve all our electrical needs and all our light transportation needs right now with domestically produced cheap clean nuclear power. Problem is politics, and unfounded fear. For example the problem with nuclear waste is mostly made up and political. Our US government does not allow spent fuel rods to be reprocessed and the unused fuel reclaimed like say France does. I mean we have enough fuel setting around collecting dust in spent rods right now to supply all our energy needs for the next twenty years and we refuse to use it.

[brantmacga]

My little brother. . . .


as a "little brother" myself, I would like to say that is a term I think all of us "younger brother's" resent.


I prefer "the more handsome brother".

or "the taller brother".

or "the one who didn't have to endure the first-born overprotectiveness of mommy and daddy, and by the time I reached 16, curfews were a thing of the past".

[cadpoint]

What does the last line have to do with what you asked?

These guys by title crunch numbers that we live with / through /and most times don't think about, bottom line is their realist and their work is based on numbers.

Frankly I enjoyed your thread and their statement till your political statement... :\

Here better yet, let them see your thread via mail, I mailed my Conversation with a business man as presented and everything here, you don't want to know the response in either case! JMO

[hardworkingstiff]

What does the last line have to do with what you asked?

These guys by title crunch numbers that we live with / through /and most times don't think about, bottom line is their realist and their work is based on numbers.

Frankly I enjoyed your thread and their statement till your political statement... :\

Here better yet, let them see your thread via mail, I mailed my Conversation with a business man as presented and everything here, you don't want to know the response in either case! JMO

CAD, uh, what are you talking about?

[brantmacga]

CAD, uh, what are you talking about?

i think me and my buddy cad might be in the same state of mind right now.

*cough* dewars

[Besoeker]

Asides from the cost being unjustifiable, the real problem with solar and wind is for every watt of renewable energy you put online, you have to build a watt standing by in a moments notice.
Or have existing conventional capacity on line running as so-called spinning reserve.
I'm a subscribed member of a sustainable energy group and I get some quite interesting articles and technical papers. There was one a while back on the intermittent nature of renewables. The conclusion that not more than 20% can come from intermittent sources. One of the reasons given was that, for anything above that level, the pollution produced by the conventional spinning reserve needed running at low efficiencies would exceed the pollution saved by the renewables.
I hope this does not take a wrong turn, but what really irritates me we have the technology and fuel supply right now to solve all our electrical needs and all our light transportation needs right now with domestically produced cheap clean nuclear power. Problem is politics, and unfounded fear.
We have a similar situation here in UK.
Many of our aging Nuclear reactors are being decommissioned. Of the remaining 19 here, all but five will be shut down within the next decade.
Politics and fear as you say.
The irony is that we import electricity from France via the Cross Channel HVDC link - and France is about 75% Nuclear.

[charlie]

Don't let this get into the political arena. The statements that democrats are liberal or that republicans are conservative are factual most of the time but are also inflammatory. I don't believe there was any intent to start any arguments so let's keep it that way. :smile:

[charlie]

. . . government does not allow spent fuel rods to be reprocessed and the unused fuel reclaimed like say France does. . .
With a little modification, we could also build the fast breeder reactor since it is now old technology. Of course we have to get rid of the radioactive waste. :smile:

[winnie]

I believe that a significant part of developing non-dispatchable power sources will be adding dispatchable _loads_ to the grid.

For example, if the wind stops blowing you could shut off storage water heaters and non-critical air conditioning.

Of course, this sort of 'smart metering' and 'demand management' is not trivial, and would require significant development. A realistic accounting of non-dispatchable power sources would include a large portion of the costs of adding these features to the grid. (IMHO not the total cost, because these same features would also help with conventional power sources and the non-dispatchable loads that are currently attached to the grid.)

With respect to nuclear power, I do not believe that it is fair to say that the only problem is politics and _unfounded_ fear. IMHO there are very real 'human nature' issues involved here. I agree that we have a handle on what would work technologically, if we could handle the human nature; but the human nature is not to be ignored.

IMHO the best technology (isolated from human nature problems) to deal with nuclear waste is reprocessing, using various reactor types to do things like produce more fuel and burn actinides. The problem that I see is that the core technology used for reprocessing fuel is what you need 'weponize' these materials. I would not call fear of nuclear proliferation 'unfounded'.

-Jon

[petersonra]

Don't let this get into the political arena. The statements that democrats are liberal or that republicans are conservative are factual most of the time but are also inflammatory. I don't believe there was any intent to start any arguments so let's keep it that way. :smile:

There was no such intent on my part. It was more along the lines of pointing out how hard facts caused him to come to a different conclusion than his political ideology would have liked. That is extremely different for most people.

This is much like the problem with dealing with the oil shortage (not that there really is one). The green house gas nonsense has pushed government into exotic energy technologies that will probably never come to be, while ignoring a technology that has potential immediately. CNG is something that just about all internal combustion engines can be converted to very rapidly. Its an abundant and very clean fuel. Yet the political ideology of global warming makes it unpalatable to the far left that now makes the decisions.

[ohm]

I believe that a significant part of developing non-dispatchable power sources will be adding dispatchable _loads_ to the grid.

For example, if the wind stops blowing you could shut off storage water heaters and non-critical air conditioning.

Of course, this sort of 'smart metering' and 'demand management' is not trivial, and would require significant development. A realistic accounting of non-dispatchable power sources would include a large portion of the costs of adding these features to the grid. (IMHO not the total cost, because these same features would also help with conventional power sources and the non-dispatchable loads that are currently attached to the grid.)

With respect to nuclear power, I do not believe that it is fair to say that the only problem is politics and _unfounded_ fear. IMHO there are very real 'human nature' issues involved here. I agree that we have a handle on what would work technologically, if we could handle the human nature; but the human nature is not to be ignored.

IMHO the best technology (isolated from human nature problems) to deal with nuclear waste is reprocessing, using various reactor types to do things like produce more fuel and burn actinides. The problem that I see is that the core technology used for reprocessing fuel is what you need 'weponize' these materials. I would not call fear of nuclear proliferation 'unfounded'.

-Jon

Shedding loads (water heaters, A/C etc.) need not be a smart grid. It could be as simple as each user installing a contactor that drops non-critical loads at a certain drop in line voltage. Like we did on submarines.

[petersonra]

Shedding loads (water heaters, A/C etc.) need not be a smart grid. It could be as simple as each user installing a contactor that drops non-critical loads at a certain drop in line voltage. Like we did on submarines.

my a/c compressor has some kind of doohickey on it that can shut it off remotely if there is a need to conserve electricity.

i get a $10 or $15 a month credit for having it. have no idea if it was ever even used.

i

[ohm]

my a/c compressor has some kind of doohickey on it that can shut it off remotely if there is a need to conserve electricity.

i get a $10 or $15 a month credit for having it. have no idea if it was ever even used.

i

Good idea. A large room/house is a great energy storage device for heat (or cold), chances are you can hardly notice if the duty cycle of your compressor is changed, but it sure helps the power company adjust for load swings.

It not only saves you electricity it also could save your compressor. Two common things that can ruin motors: low voltage and high voltage.

[Besoeker]

Don't let this get into the political arena. The statements that democrats are liberal or that republicans are conservative are factual most of the time but are also inflammatory. I don't believe there was any intent to start any arguments so let's keep it that way. :smile:
My mention of politics was just that. Not what side of the house they sit on.
It isn't a political debate - more a comment on how government works in general.

In UK, successive governments (of both flavors) have sat on their hands so long over the Nuclear issue that the "power crunch" is inevitable.
This has been widely covered in the technical press here for some years now.
I think one of the problems is that Nuclear has been seen as unpalatable by the electorate - or maybe just perceived that way by the political establishment.
The gestation period for new build nuclear is longer than the period between general elections here, so maybe no government would want to risk making an unpopular decision that would get them booted out of office.

For whatever reason, until recently, no new sanctions to build nuclear had been given for about 30 years.

[ohm]

My mention of politics was just that. Not what side of the house they sit on.
It isn't a political debate - more a comment on how government works in general.

In UK, successive governments (of both flavors) have sat on their hands so long over the Nuclear issue that the "power crunch" is inevitable.
This has been widely covered in the technical press here for some years now.
I think one of the problems is that Nuclear has been seen as unpalatable by the electorate - or maybe just perceived that way by the political establishment.
The gestation period for new build nuclear is longer than the period between general elections here, so maybe no government would want to risk making an unpopular decision that would get them booted out of office.

For whatever reason, until recently, no new sanctions to build nuclear had been given for about 30 years.

The nuclear age got off to a bad start, everyone is afraid of it. But really, it's the safest form of energy we have. And, it doesn't cost more than another nickel to store and guard 1000 tons of nuclear waste than 2000 tons, if you don't feel like reusing it.

[dereckbc]

my a/c compressor has some kind of doohickey on it that can shut it off remotely if there is a need to conserve electricity.

i get a $10 or $15 a month credit for having it. have no idea if it was ever even used. iActually that technology has been around for quite some time, and implemented by many POCO's since the early 80's under various market names.

It is very simple the POCO installes a radio reciever on your compressor unit that opens the compressor contol circuit shutting off your compressor. When I worked at PSO in Tulsa OK the program was called Good-Cents, and during peak times the POCO would interupt your Ac unit 15 minutes out of every hour in a rotation around the city. It allowed then to shed enough load during peak hours so they did not have to build extra generating capacity or purchase from the grid at much higher prices.

[don_resqcapt19]

Shedding loads (water heaters, A/C etc.) need not be a smart grid. It could be as simple as each user installing a contactor that drops non-critical loads at a certain drop in line voltage. Like we did on submarines.
There is working being done to tie the drop out of loads to the frequency of the grid as that is a better indication of the total grid load than a local voltage change.

[ohm]

There is working being done to tie the drop out of loads to the frequency of the grid as that is a better indication of the total grid load than a local voltage change.

You would think that the drop in frquency at the generator(s) would be indicative of total load but you still would not know how much and from what direction.

[don_resqcapt19]

You would think that the drop in frquency at the generator(s) would be indicative of total load but you still would not know how much and from what direction.
It really doesn't matter. There are 3 interconnect grids in the US and any load or generation change within a grid has an effect on the grid frequency. As you get a larger distance away from the point of the frequency disturbance, the magnitude of the disturbance is dampened.

[ohm]

It really doesn't matter. There are 3 interconnect grids in the US and any load or generation change within a grid has an effect on the grid frequency. As you get a larger distance away from the point of the frequency disturbance, the magnitude of the disturbance is dampened.

Don, you obviously know more about the Grid than I do. Maybe you can bring us up to speed.

Is it true that if an entire city goes down the grid is not capable of supplying it?

What's the % loss/mile on the grid?

I've heard there is a long wait (3 yrs) for someone doing co-generation to get tied-in to the grid.

Thanks

[don_resqcapt19]

I don't know a lot about it. If a city or area is dropped out that is a result of the loss of transmission lines that feed the the area. This could be physical damage or the result of the protective relays doing their job...protecting the grid. In theory the outage should be localized but in some cases the combination of the loads and other conditions on the grid result in a wide spread blackout.
When a large amount of load drops off line (a city or area) the frequency on the rest of the grid will rise and if it rises too much the generators will trip off on over frequency and sometimes these are the conditions that cascade the outage to a large blackout. The same can happen the other way when a very large load is placed on the system and the frequency drops too much the generators will trip off on under frequency.
I don' know what the grid loss is.
There is a wait in some areas. There is a lot of engineering that is required when generation of any size is tied into the grid, but sometimes it is just the local utility that doesn't really want the cogen connected to their distribution system.

[ohm]

I don't know a lot about it. If a city or area is dropped out that is a result of the loss of transmission lines that feed the the area. This could be physical damage or the result of the protective relays doing their job...protecting the grid. In theory the outage should be localized but in some cases the combination of the loads and other conditions on the grid result in a wide spread blackout.
When a large amount of load drops off line (a city or area) the frequency on the rest of the grid will rise and if it rises too much the generators will trip off on over frequency and sometimes these are the conditions that cascade the outage to a large blackout. The same can happen the other way when a very large load is placed on the system and the frequency drops too much the generators will trip off on under frequency.
I don' know what the grid loss is.
There is a wait in some areas. There is a lot of engineering that is required when generation of any size is tied into the grid, but sometimes it is just the local utility that doesn't really want the cogen connected to their distribution system.

The reason I ask about transmission between power plants is I heard because of very high transmission losses one plant can't really take over for another, even if they had the capacity.

Since the bulk of of power generation is rotational sources I guess frequency actually is a good indicator of load. I wonder if Solar PV becomes more common if frequency will still be a good indicator of load, since inverters will be the prime movers?

Also, how great is the storage effect of parallel transmission lines? I heard the POCO's have to discharge them even after the disconnects are opened, before doing maintenance.

Utilities are another world to most of us, thanks.

[dereckbc]

The reason I ask about transmission between power plants is I heard because of very high transmission losses one plant can't really take over for another, even if they had the capacity.Ohm i can answer some of your questions as I use to be a POCO Sub Station Relay Controll engineer years ago. I know Charlie E another Mod can if he picks up on this.

POCO's all work in parallel through the grid. Loosing just one generator is usually not a problem since there is more than one in parallel. Not to say it cannot be a problem, but generally it is not.


Since the bulk of of power generation is rotational sources I guess frequency actually is a good indicator of load. I wonder if Solar PV becomes more common if frequency will still be a good indicator of load, since inverters will be the prime movers?Well if you are talking residential grid-tied solar PV, the inverters used in that application are synced to the grid and the frequency tracks the POCO. In the event of a power failure the grid-tied inverter disconnects as designed and required.


Also, how great is the storage effect of parallel transmission lines? I heard the POCO's have to discharge them even after the disconnects are opened, before doing maintenance. You are talking two seperate issues. One is static electricity, and the other is protection from accidental reclosrue. Lineman do ground the lines when working to protect themselves. Since the lines are overhead and wind blowing the ground discharges the static build up on the lines. Also in the event there is a accidental reclosure on the line, the ground will trip the realys back at the sub station and de-energize the lines.

[Besoeker]

It really doesn't matter. There are 3 interconnect grids in the US and any load or generation change within a grid has an effect on the grid frequency. As you get a larger distance away from the point of the frequency disturbance, the magnitude of the disturbance is dampened.
But surely they all still need to be the same frequency?

[ohm]

But surely they all still need to be the same frequency?

Thanks Don. Looks like we'll be seeing a lot about infrastructure in the future.

[don_resqcapt19]

But surely they all still need to be the same frequency?
The frequency is the "same" through out the interconnect, but there are load and generation changes within the interconnect that create small frequency disturbances. These propagate across the complete interconnect much like the small waves created when you toss an object into water. The magnitude of the frequency disturbance is dampened as you move away from the source. I have been told that the propagation speed of the frequency disturbance movement across the interconnect is about 1/3 the speed of light, but don't have a document to back that up.

If you are asking about the frequency of the 3 interconnects, yes the base frequency is 60 hertz, but they are not in sync with each other. There are no direct connections between the interconnects for this reason.

[Besoeker]

If you are asking about the frequency of the 3 interconnects, yes the base frequency is 60 hertz, but they are not in sync with each other. There are no direct connections between the interconnects for this reason.
If there are no direct connections, how are the three grids interconnected?

[don_resqcapt19]

If there are no direct connections, how are the three grids interconnected?
There are some connections using inverters to sync one interconnect with another. I thing there may be other methods that are also used to make connections between the grids. The 3 interconnect grids in the US are east of the Rockies, west of the Rockies and Texas. Everything within an interconnect grid is connected together, but there are very few connections between the grids.

[Mr. Bill]

The 3 interconnect grids in the US are east of the Rockies, west of the Rockies and Texas.
Texas is still doing the whole lone star thing, even with energy.

[Besoeker]

There are some connections using inverters to sync one interconnect with another.
You mean a DC link, perhaps?

[don_resqcapt19]

You mean a DC link, perhaps?
Yes, that has been done, but sometimes it is just one piece of equipment, much like a VFD where you bring the power into it from one grid and you take the output to the other grid. There are others where there are DC transmissing lines between two interconnects with converters at each end.

[Besoeker]

Yes, that has been done, but sometimes it is just one piece of equipment, much like a VFD where you bring the power into it from one grid and you take the output to the other grid.
That's what I meant by a DC link. (Not transmission.)
A converter to get from AC to DC then an inverter, possibly mains commutated, to get it back to AC.
Not quite sure I see the point for the sort powers at grid interconnector level though, unless you are going to take advantage HVDC transmission.
Most of the alternators I have dealt with are automatically synchronised to grid frequency, closed on to the bars and subsequently controlled by a static exciter, generally on voltage, sometimes with a bit of VAr compensation.
You can't get them out of sync. You can't close up until you have synchronisation in both phase and frequency.
Once closed, if there was any tendency towards getting out of sync, they would trip on some parameter, maybe overcurrent, excessive VArs, reverse power etc. before that happened.

Having said that, my direct experience is on alternators up to 30 MVA which, for grid-connected units, is relatively small but I have seen similar systems used on machines

[don_resqcapt19]

...
Most of the alternators I have dealt with are automatically synchronised to grid frequency, closed on to the bars and subsequently controlled by a static exciter, generally on voltage, sometimes with a bit of VAr compensation.
You can't get them out of sync. You can't close up until you have synchronisation in both phase and frequency.
Once closed, if there was any tendency towards getting out of sync, they would trip on some parameter, maybe overcurrent, excessive VArs, reverse power etc. before that happened. ...
That is true. To tie a source to the grid it must be synced with the grid and once it is tied to the grid it will remain in sync with the grid. The issue is that there are 3 interconnect grids in the US and they are not in sync with each other. Any transfer of power between the grids requires some device to transfer power between the out of sync grids. Sometimes there is excess power available or power at a cheaper rate available in the ajoining grid and such a device lets you transfer this power to where it is needed.

[Besoeker]

That is true. To tie a source to the grid it must be synced with the grid and once it is tied to the grid it will remain in sync with the grid. The issue is that there are 3 interconnect grids in the US and they are not in sync with each other. Any transfer of power between the grids requires some device to transfer power between the out of sync grids.
Do you have any specific details of those devices and their power ratings?

[Fulthrotl]

i think me and my buddy cad might be in the same state of mind right now.

*cough* dewars

please, before hitting send, blow into this little tube attached on the monitor......

thweee.... thweee..... HARDER..... THWEEEEEEEE!!!!!!!.......

thank you.... analyzing now....... mr. macga, please step away from
the keyboard, and place your hands behind you........:D

it gets even uglier than that:

http://www.marcryan.com/steve/index.html

[don_resqcapt19]

Do you have any specific details of those devices and their power ratings?
I haven't looked at that too much, but here (http://www.abb.com/cawp/gad02181/b12c1d8468eee62bc12570c80038289b.aspx) is one with a 150 MW capacity. There is also something called a VFT (variable frequency transformer) (http://www.gepower.com/prod_serv/products/transformers_vft/en/downloads/ipst05_paper075.pdf) that can be used for this purpose.

[ohm]

I haven't looked at that too much, but here (http://www.abb.com/cawp/gad02181/b12c1d8468eee62bc12570c80038289b.aspx) is one with a 150 MW capacity. There is also something called a VFT (variable frequency transformer) (http://www.gepower.com/prod_serv/products/transformers_vft/en/downloads/ipst05_paper075.pdf) that can be used for this purpose.

Cool, we've come a long way from simple generation & distribution. I for one am starting to form a new appreciation for our POCO's.

[don_resqcapt19]

Here is a link (http://www.energy.siemens.com/cms/us/US_Products/Portfolio/HVSystemsupto800kV/HighVoltageDCTransmissionSystems/Documents/HVDC_References.pdf) to some HVDC systems that were made by Siemens. They range in capacity from 55 MW to 3100MW. Some are used to match the frequency between two girds, and other are used for long distance high power transmission circuits.

[gadfly56]

What's the % loss/mile on the grid?



I can't answer that directly, but I understand that overall transmission losses are about 50%. Sorry, can't remember where I picked that up.

[petersonra]

I can't answer that directly, but I understand that overall transmission losses are about 50%. Sorry, can't remember where I picked that up.

I have seen a number like that as well. supposedly a "smart grid" will somehow reduce the losses.

[don_resqcapt19]

This document (http://climatetechnology.gov/library/2003/tech-options/tech-options-1-3-2.pdf) estimates the US transmission and distribution losses at 7.2%.

[ohm]

This document (http://climatetechnology.gov/library/2003/tech-options/tech-options-1-3-2.pdf) estimates the US transmission and distribution losses at 7.2%.

Great article Don.

The composite core low sag lines seem likea good way to double or even tripple their effectiveness without having to beef up the towers. 3M may be a company to watch.

Does DC transmission lines offer a storage (capacitive) effect and get away from the skin effect we see w/ AC?

How important is a "Smart Grid" i.e. GPS, Sat. clocks etc. ?

Is there anything in the works to improve transformer losses and how good are inverters (thyristors).

I think I was misled by the 50% T/D losses number we all heard but couldn't pin down. But it seems that was the split between T & D of the 7.2% total loss, which seems much more reasonable.

[charlie]

. . . I know Charlie E another Mod can if he picks up on this. . .
I have intentionally stayed out of this discussion. I am not an engineer, have never worked in relaying, substation design, or transmission line design. My expertise is in distribution and codes and standards. I am familiar with some of the things you guys have talked about but don't have the basic knowledge to enter the conversation. This is an interesting conversation though, especially about the Texas interconnection. It is interesting to me that Texas has a treaty with the US that permits it to secede from the union and it may also divide itself into either 3 or 5 states with all of the rights of a state. :smile:

[Cold Fusion]

It really doesn't matter. There are 3 interconnect grids in the US and any load or generation change within a grid has an effect on the grid frequency. As you get a larger distance away from the point of the frequency disturbance, the magnitude of the disturbance is dampened.
don -
Would "phase" or "phase differential" be a better description than "frequency"?

I'm thinking that if the the phase angle is off far enough to be a frequency disturbance, then one of the generators is exceeding a 90deg power angle and is slipping a pole.

Maybe it is just a semantics issue. But the idea of a frequency "disturbance" for two gens tied together - brings to mind the poles of one gen going by the poles of other --- ouch!

cf

[Cold Fusion]

---A converter to get from AC to DC then an inverter, possibly mains commutated, to get it back to AC.
Not quite sure I see the point for the sort powers at grid interconnector level though, unless you are going to take advantage HVDC transmission. ---
As I recall (400 level class in transmission - 23 years ago - recollection could be a bit fuzzy) short DC links are put in for stability reasons. The two examples we worked were James Bay Hydro AC transmission to a back to back, DC link at Niagra Falls; and a 30 mile (kilometer?) under water, DC link to Goat Island, Norway. These two DC links were put in to prevent stability problems associated with AC links.

carl

[don_resqcapt19]

don -
Would "phase" or "phase differential" be a better description than "frequency"?

I'm thinking that if the the phase angle is off far enough to be a frequency disturbance, then one of the generators is exceeding a 90deg power angle and is slipping a pole.

Maybe it is just a semantics issue. But the idea of a frequency "disturbance" for two gens tied together - brings to mind the poles of one gen going by the poles of other --- ouch!

cf
The amount of frequency deviation is small. I think that the protective relaying starts tripping generators and circuits off line with a deviation of 0.2 hertz or so. When there is a large load change or generation change, the frequency of the grid in that area changes. As that change ripples across the grid it is dampened. It is my understanding that even though everything in a grid is physically connected together the frequency is not exactly the same across the whole interconnect. Not really sure how this works.
I guess we need a transmission engineer to help us out with this. My information is only from things I have read. It is a subject that I am interested in, but I am not an engineer and don't really understand all I have read about how the grid works.
There are not too many people that really do. A EE with a PhD that has worked on the US grid for the last 40 years stated the following on another forum..."there are less than 100 people that really understand how the power grid functions, and I am not one of those people. It has been said that the power transmission and distribution sytem is the most complicated machine that has ever been built.

[dereckbc]

Texas has a treaty with the US that permits it to secede from the union and it may also divide itself into either 3 or 5 states with all of the rights of a state. :smile:Not entirely true.
http://www.texassecede.com/faq.htm
However there is nothing to prevent Texas from secedeing, all it takes is a vote of the people of TX. There are several organazations in th estate pushing hard since the new administration took office and it is gaining traction.

[McGowdog]

as a "little brother" myself, I would like to say that is a term I think all of us "younger brother's" resent.


I prefer "the more handsome brother".

or "the taller brother".

or "the one who didn't have to endure the first-born overprotectiveness of mommy and daddy, and by the time I reached 16, curfews were a thing of the past".

That's it! One of my "older" and "bigger" brothers calls me his "little" brother. Now he goes about 305 and he DID have the lap-band proceedure, but he stands about 5'10". I'm the only one in the family (youngest of 4 bros) who is 6'0". I thought my dad was taller, but either he shrunk or I got taller. I like that. I'm the taller brother; and I concur with the curfew thing.

What about a tower, like I saw on the History Channel, that captures the collected sun rays from mirrors... and a wind tower? Both, but with a nuclear energy backup? The wind and solar novelties could be good visual for the Greenies, and the nuclear could do the grunt work!:cool:

[Besoeker]

Here is a link (http://www.energy.siemens.com/cms/us/US_Products/Portfolio/HVSystemsupto800kV/HighVoltageDCTransmissionSystems/Documents/HVDC_References.pdf) to some HVDC systems that were made by Siemens. They range in capacity from 55 MW to 3100MW. Some are used to match the frequency between two girds, and other are used for long distance high power transmission circuits.
Interesting link. I didn't know that asynchronous gereration existed for major power generation in USA, or anywhere for that matter.
I can now see why back to back ac-dc-ac systems would be required for applications other than long distance transmission.

And it maybe explains why there is such a long delivery on LASCR's.....