you can already do this - I made a perl script that took the contents of a web - form, inserted it into a.doc form (converted to odf) and then printed it as PDF and emailed the PDF file to the powers that be.
yeah, so there are already perl modules to do what this toolkit is about. no surprise there!
this is the key that you are omitting "Remember that in the transmission line - the resistor that it forms - doesn't see the voltage it is carrying(an apocryphal concept actually), it sees the voltage that is dropped across it, i.e. it only sees I2R losses."
You could have a line engergized to 500kV without any current running through it at all - assuming both endpoints are at exactly 500kV.
As soon as current starts to flow, you will have a potential drop across the transmission line due to the I^2R losses. this potential drop Vdrop=V1-V2 where 1 and 2 are the line endpoints, is the V in V=IR you are thinking about.
You can't up the voltage without increasing the current seems false to me.
what exactly is wrong with saying that there is such a thing as transmission congestion? Is there a better term for it, or do you dispute that it exists?
They built one or more (gas fired in this case) power plants in downtown Toronto because there wasn't enough transmission capacity to get enough power to the load at peak times.
Yes, it would be nice if loads had some generation nearby, renewable or otherwise, that would help reduce the need for additional transmission capacity. I think they call that distributed generation.
maybe for A to B long distance runs with no stops in between, but it is difficult/expensive to step the voltage up and down at any places where power is delivered to loads or injected from generators
I don't believe it is possible to alter the speed of a synchronous machine generator connected to the grid.
You put less power in, you get less power out. You can't alter the speed unless it is not connected to the grid or unless maybe your generator is VERY large or your grid is VERY small.
I don't know what argument you are referring to. The GP said that transmission lines, which are insulated for a specific (and fixed) voltage, don't get congested.
For a certain fixed voltage there is a limit to how much current can flow before there is no more capacity.
Why can the european grid handle so much wind when the US one can't? What is the difference between them? I can't think of much apart from 50/60Hz and that the distance between the proposed windfarms and loads in the US is much greater. Perhaps the distance is the problem. With transmission lines, distance may be directly proportional to cost...
While electricity prices do vary from state to state, how much of a discrepancy do you think people could handle before their heads exploded?
"why should they only pay 7cents a kwh just because they live under a wind turbine while I have to pay 25cents because I'm in (the middle of nowhere near a generator|the middle of somewhere very busy where lots of people use lots of electricity)."
In northern ontario the electricity could be very cheap, there are is a lot of coal fired generation and lots of industry has shutdown so there isn't much load. There is also very little transmission capacity so the generation is "bottled in". Sorry for the PDF link
Power should be cheaper there than in downtown Toronto but everybody pays the same price. Just like for beer in Ontario, which is only sold by the government, it costs the same from the government beer store in the middle of nowhere as it does in the middle of downtown toronto, although in that case you'd expect it to be cheaper in toronto.
pumped storage is common and works great if you have the geography. France uses it extensively with their baseload nuclear to pump water uphill at night and then run it back down during the day
I can't imagine the size of the inverter you would need - it would be far larger than anything like that ever made.
wouldn't you need a 100MW inverter? What do they do at the end of 100MW DC transmission lines. Maybe have a DC generator turning an AC one? It may not be an typical power-electronics inverter but it would perform the same function with 90% efficiency (assuming both ac and dc motors were 95% efficient)
DC lines can be higher voltage than AC lines. one line is +345 kV while the other is -345kV and so you have a 700kV line without all the funnythings that start to happen when you have AC lines that are 700+ kV.
higher voltage means more power for the same current or less losses for the same power if you want to look at it that way.
Then also since it is DC there is no capacitance and I think you get further reduction in losses from that.
Here is a model for an AC transmission line showing all the capacitance etc
A wire has a given amount of current that can flow through it before it melts. Take a thin wire and connect it to the + and - terminals on your car battery (use thick leather gloves so you don't get burned) and see what happens when you stuff too much power down a wire.
Here is a link to the outfit that runs the grid in Ontario. When a generator wants to generate but can't due to the fact that there isn't enough transmission capacity to get the power out of their plant they get "constrained off", ie they don't generate. The link talks about how much they get paid for not generating.
Must be nice to get paid for doing nothing.
But anyway, wires do get congested but not the same way your nose does.
cost. and nobody wants a higher electricity bill. batteries that large are expensive and then you need equipment to change it from ac to dc etc. I've seen one large enough to power a military base for 2-3 days, it was 30 feet high, 30 feet long and 60 feet wide.
How is our grid not smart enough as it is? It may have limited capacity, but what more do you want it to do! It already disconnects circuits with faults on them to protect itself...what else is there (other than controlling demand, which is maybe more smart loads than smart grid) adaptive: if there is a path for electricity to flow it will, no adapting required switching: every Tx line has circuit breakers and reclosers etc...no shortage of 'switches' there.
When people say smart grid I never know what they mean. Some people are talking transition from analog to digital and I get that but to be honest I've not seen a whole lot of analog electro-mechanical gear... it is being replaced by new digital relays rather quickly
while those are really cool, I think only worth the cost when you need to move a lot of power and have limited physical space (ie not enough to fit the required number of non-superconducting conductors).
transmission capacity is a limited resource, so when supply gets tight the cost goes up. TFA said they didn't want to pay the increased cost of transmission: "...become so congested that the companyâ(TM)s only choice is to shut down â" or pay fees for the privilege of continuing to pump power into the lines."
Somebody else is clearly willing to pay the increased cost of transmission - meaning they can do so and still make their profit.
Sure the losses are less, so you save some money there, but the equipment at each substation has got to be a lot more expensive. So maybe HVDC is best at transporting large amounts of power from A to B, but not making any stops along the way.
Another handy use may be for an intertie between parts of the grid that are not synchronized but I think there are alternatives (phase shifters?) for this as well which are cheaper
The next time you drive by a nuclear plant take a look at the transmission infrastructure. You might see three different sets of pylons leaving each with a couple of 500kV circuits.
It takes wires to move electricty from generation to load, I don't know why they are surprised that when they build a wind farm in the middle of nowhere there transmission capacity to handle all that extra energy.
Especially since everybody says they have hardly built anything new in the way of transmission...of course there is no spare capacity!
Slashdot Mirror
They are installing a prototype wave powered generator on maui. There are concerns that birds will be sucked through the turbine.
Oceanlinx is the company
you can already do this - I made a perl script that took the contents of a web - form, inserted it into a .doc form (converted to odf) and then printed it as PDF and emailed the PDF file to the powers that be.
yeah, so there are already perl modules to do what this toolkit is about. no surprise there!
I've been using radio mobile and it does a great job for my needs
don't forget to factor in some inflation.
this is the key that you are omitting
"Remember that in the transmission line - the resistor that it forms - doesn't see the voltage it is carrying(an apocryphal concept actually), it sees the voltage that is dropped across it, i.e. it only sees I2R losses."
You could have a line engergized to 500kV without any current running through it at all - assuming both endpoints are at exactly 500kV.
As soon as current starts to flow, you will have a potential drop across the transmission line due to the I^2R losses. this potential drop Vdrop=V1-V2 where 1 and 2 are the line endpoints, is the V in V=IR you are thinking about.
You can't up the voltage without increasing the current seems false to me.
what exactly is wrong with saying that there is such a thing as transmission congestion? Is there a better term for it, or do you dispute that it exists?
They built one or more (gas fired in this case) power plants in downtown Toronto because there wasn't enough transmission capacity to get enough power to the load at peak times.
Yes, it would be nice if loads had some generation nearby, renewable or otherwise, that would help reduce the need for additional transmission capacity. I think they call that distributed generation.
maybe for A to B long distance runs with no stops in between, but it is difficult/expensive to step the voltage up and down at any places where power is delivered to loads or injected from generators
I don't believe it is possible to alter the speed of a synchronous machine generator connected to the grid.
You put less power in, you get less power out. You can't alter the speed unless it is not connected to the grid or unless maybe your generator is VERY large or your grid is VERY small.
I don't know what argument you are referring to.
The GP said that transmission lines, which are insulated for a specific (and fixed) voltage, don't get congested.
For a certain fixed voltage there is a limit to how much current can flow before there is no more capacity.
a thin wire is going to melt in less than 1s like a fuse. no explosions here
Would it be worthwhile to convert some AC lines to DC?
really, the phases get out of sync over large distances?
Due to small differences in the impedance of the individual conductors/insulators/transformer coils that make up the circuit?
how is this problem dealt with?
Why can the european grid handle so much wind when the US one can't?
What is the difference between them? I can't think of much apart from 50/60Hz and that the distance between the proposed windfarms and loads in the US is much greater. Perhaps the distance is the problem. With transmission lines, distance may be directly proportional to cost...
While electricity prices do vary from state to state, how much of a discrepancy do you think people could handle before their heads exploded?
"why should they only pay 7cents a kwh just because they live under a wind turbine while I have to pay 25cents because I'm in (the middle of nowhere near a generator|the middle of somewhere very busy where lots of people use lots of electricity)."
In northern ontario the electricity could be very cheap, there are is a lot of coal fired generation and lots of industry has shutdown so there isn't much load. There is also very little transmission capacity so the generation is "bottled in".
Sorry for the PDF link
Power should be cheaper there than in downtown Toronto but everybody pays the same price. Just like for beer in Ontario, which is only sold by the government, it costs the same from the government beer store in the middle of nowhere as it does in the middle of downtown toronto, although in that case you'd expect it to be cheaper in toronto.
pumped storage is common and works great if you have the geography. France uses it extensively with their baseload nuclear to pump water uphill at night and then run it back down during the day
I can't imagine the size of the inverter you would need - it would be far larger than anything like that ever made.
wouldn't you need a 100MW inverter?
What do they do at the end of 100MW DC transmission lines. Maybe have a DC generator turning an AC one? It may not be an typical power-electronics inverter but it would perform the same function with 90% efficiency (assuming both ac and dc motors were 95% efficient)
DC lines can be higher voltage than AC lines. one line is +345 kV while the other is -345kV and so you have a 700kV line without all the funny things that start to happen when you have AC lines that are 700+ kV.
higher voltage means more power for the same current or less losses for the same power if you want to look at it that way.
Then also since it is DC there is no capacitance and I think you get further reduction in losses from that.
Here is a model for an AC transmission line showing all the capacitance etc
A wire has a given amount of current that can flow through it before it melts. Take a thin wire and connect it to the + and - terminals on your car battery (use thick leather gloves so you don't get burned) and see what happens when you stuff too much power down a wire.
Here is a link to the outfit that runs the grid in Ontario. When a generator wants to generate but can't due to the fact that there isn't enough transmission capacity to get the power out of their plant they get "constrained off", ie they don't generate. The link talks about how much they get paid for not generating.
Must be nice to get paid for doing nothing.
But anyway, wires do get congested but not the same way your nose does.
cost. and nobody wants a higher electricity bill. batteries that large are expensive and then you need equipment to change it from ac to dc etc.
I've seen one large enough to power a military base for 2-3 days, it was 30 feet high, 30 feet long and 60 feet wide.
How is our grid not smart enough as it is?
It may have limited capacity, but what more do you want it to do! It already disconnects circuits with faults on them to protect itself...what else is there (other than controlling demand, which is maybe more smart loads than smart grid)
adaptive: if there is a path for electricity to flow it will, no adapting required
switching: every Tx line has circuit breakers and reclosers etc...no shortage of 'switches' there.
When people say smart grid I never know what they mean. Some people are talking transition from analog to digital and I get that but to be honest I've not seen a whole lot of analog electro-mechanical gear ... it is being replaced by new digital relays rather quickly
while those are really cool, I think only worth the cost when you need to move a lot of power and have limited physical space (ie not enough to fit the required number of non-superconducting conductors).
transmission capacity is a limited resource, so when supply gets tight the cost goes up. TFA said they didn't want to pay the increased cost of transmission:
"...become so congested that the companyâ(TM)s only choice is to shut down â" or pay fees for the privilege of continuing to pump power into the lines."
Somebody else is clearly willing to pay the increased cost of transmission - meaning they can do so and still make their profit.
hydro and fossil driven turbines have constant RPMs if they are attached to a synchronous generator, which they usually are.
To reduce the power out they reduce the power in (ie use less water/steam/coal/gas/whatever)
is HVDC really that great?
Sure the losses are less, so you save some money there, but the equipment at each substation has got to be a lot more expensive. So maybe HVDC is best at transporting large amounts of power from A to B, but not making any stops along the way.
Another handy use may be for an intertie between parts of the grid that are not synchronized but I think there are alternatives (phase shifters?) for this as well which are cheaper
The next time you drive by a nuclear plant take a look at the transmission infrastructure. You might see three different sets of pylons leaving each with a couple of 500kV circuits.
It takes wires to move electricty from generation to load, I don't know why they are surprised that when they build a wind farm in the middle of nowhere there transmission capacity to handle all that extra energy.
Especially since everybody says they have hardly built anything new in the way of transmission...of course there is no spare capacity!