my chrome dev build on ubunutu 8.04 is messed up right now. select boxes don't show the options and tabs are freezing, which has never happened before.
In the daily ubuntu chromium-browser build they have the select boxes fixed but still has random freezing.
By switching transmission lines in and out, or by cross-connecting circuits, a whole substation or generating plant could be taken out for months. Really? As I've seen it there are commands the operators can give via scada systems, remotely (from a different city), or locally (from the control room), but none of them could result in destroying assets as the safety systems operate a level beneath the commands.
If you close a circuit onto another one that is out of phase, it trips.
If you have a line that is used at two different voltages depending on what it is connecting to and from, and you hook the 66kV up to the 33, it trips. that could be an ugly scenario though.
If you dump the load off the generator and it goes into overspeed, it trips.
From what I've seen, which is albeit limited, the control systems expose some functionality, but the safety systems will override those commands unless the equipment is set to "local" or possibly "manual" which normally has to be done via a hard switch within sight of the actual equipment.
I couldn't wreck the power stations I work on with out getting in to the control system. then it would be easy to spin it to bits.
For plant to be taken out for months, it really needs a catastrophic failure like a transformer exploding, fault on the generator, damage to penstock/turbine etc, or maybe you can explain how switching a transmission line in and out could wreck plant for months?
all radio communications are totally vulnerable to being jammed. There is no way around it.
And fibres are easily cut. Just run your truck into a pole and down they go or get your trenching tool and dig them up or if you are in the med drop your anchor.
Systems fail without human intervention, something as large and ubiquitous as the power grid and the communication infrastructure for the 'smart' grid basically can't be protected.
half the voltage = twice the current for the same power, P=I^2R so the resistive losses go up by 4x which means 4x more heat = melting or blown cheap electronics and power supplies.
i hear what you're saying. don't take people's money off them and let them spend it or invest it as they see fit.
What do you think everyone would have bought with that money? I think it is $6.8*10^11/350*10^6 americans is $1,900 per american.
not an insignificant amount of money! a months rent, your books for a year at school, a shitty car...or I suppose investment in a company which may or may not be involved in providing infrastructure, health care, whatever.
I like the idea of small government where ever possible, but there must be some things that only governments have the resources for and can assume the risk.
microwaves can be jammed and fibre can be cut, will the communications network become just as critical to the operation of the power grid as the generators and transmission lines themselves!
it's really quite impressive that the grid stays up as much as it does. there is a trade off between cost and uptime, it is probably an exponential relationship and we're already at 99.9999% uptime, so how much more is that extra.0001% worth?
ah so you would like to pay extra on your electricity bill for a separate, coast to coast, nationwide fibre optic and microwave data network which exists everywhere there is electricity?
the point was imagine the public transport (rail, roads,etc), health care, the U.S. could have had with that 680 billion. or even just a fraction of it...
there's the attitude: There is always somebody out there smarter than you, and there is always going to be a bug or security vulnerability somewhere in the system.
There was an interesting blog in the economist magazine pondering what else could be done with the 680 billion the US spends annually on defense.
While the US has spent a trillion in Iraq the chinese have spent a trillion improving their infrastructure.
Also, the electronics can supply as much reactive effect as the peak effect of the wind turbines even when the turbines are completely stopped.
can you expand on this? Is it a synchronous machine inside a wind turbine? They can be used as a synchronous condenser to supply reactive power when the turbine is stopped?
power generated locally is worth more too. wholesale prices generators get paid are 3-7 cents/kwh without fancy government contracts while power delivered to a customer's house is worth 20-30 cents/kwh. so while it is expensive to permit and build a big plant, transmission and distribution are also expensive.
"he story notes that mobile data at AT&T has grown 4,932% over the last 3 years."
3 years ago mobile data traffic was probably nearly zero, so putting this in relative terms means nothing to me.
I wonder how much traffic their feeble network is actually dealing with? Imagine it was only 100 MB/s off each cell site and they are whinging like this...
skype on windows has become a piece of shit! The linux version does everything except for SMS messages and hasn't become a UI nightmare. let's keep it that way
hi, the device has already shorted out. a short circuit has nearly zero resistance, and thus nearly infinite current will flow. nearly infinity (ok well probably more like 100 Amps) is much larger than 15 or 30 so a short circuit will trip the circuit breaker no matter what it is rated for.
some mobile internet dongles have 2gb flash memory in them that is mounted as a drive for your reading and writing pleasure. sometimes they stick the driver for the dongle on there.
so your mobile internet dongle may be a hard drive as well, hence the usb-storage.
Slashdot Mirror
my chrome dev build on ubunutu 8.04 is messed up right now. select boxes don't show the options and tabs are freezing, which has never happened before.
In the daily ubuntu chromium-browser build they have the select boxes fixed but still has random freezing.
By switching transmission lines in and out, or by cross-connecting circuits, a whole substation or generating plant could be taken out for months.
Really?
As I've seen it there are commands the operators can give via scada systems, remotely (from a different city), or locally (from the control room), but none of them could result in destroying assets as the safety systems operate a level beneath the commands.
If you close a circuit onto another one that is out of phase, it trips.
If you have a line that is used at two different voltages depending on what it is connecting to and from, and you hook the 66kV up to the 33, it trips. that could be an ugly scenario though.
If you dump the load off the generator and it goes into overspeed, it trips.
From what I've seen, which is albeit limited, the control systems expose some functionality, but the safety systems will override those commands unless the equipment is set to "local" or possibly "manual" which normally has to be done via a hard switch within sight of the actual equipment.
I couldn't wreck the power stations I work on with out getting in to the control system. then it would be easy to spin it to bits.
For plant to be taken out for months, it really needs a catastrophic failure like a transformer exploding, fault on the generator, damage to penstock/turbine etc, or maybe you can explain how switching a transmission line in and out could wreck plant for months?
all radio communications are totally vulnerable to being jammed. There is no way around it.
And fibres are easily cut. Just run your truck into a pole and down they go or get your trenching tool and dig them up or if you are in the med drop your anchor.
Systems fail without human intervention, something as large and ubiquitous as the power grid and the communication infrastructure for the 'smart' grid basically can't be protected.
. All these pieces of embedded equipment have their own stuff, and the knowledge tends to be very specialized.
How do you feel about 61850
I haven't had the opportunity to work with it hands-on myself yet, just watch other people with the new gear and drool
half the voltage = twice the current for the same power, P=I^2R so the resistive losses go up by 4x which means 4x more heat = melting or blown cheap electronics and power supplies.
i hear what you're saying. don't take people's money off them and let them spend it or invest it as they see fit.
What do you think everyone would have bought with that money? I think it is $6.8*10^11/350*10^6 americans is $1,900 per american.
not an insignificant amount of money! a months rent, your books for a year at school, a shitty car...or I suppose investment in a company which may or may not be involved in providing infrastructure, health care, whatever.
I like the idea of small government where ever possible, but there must be some things that only governments have the resources for and can assume the risk.
microwaves can be jammed and fibre can be cut, will the communications network become just as critical to the operation of the power grid as the generators and transmission lines themselves!
it's really quite impressive that the grid stays up as much as it does. there is a trade off between cost and uptime, it is probably an exponential relationship and we're already at 99.9999% uptime, so how much more is that extra .0001% worth?
ah so you would like to pay extra on your electricity bill for a separate, coast to coast, nationwide fibre optic and microwave data network which exists everywhere there is electricity?
the point was imagine the public transport (rail, roads,etc), health care, the U.S. could have had with that 680 billion. or even just a fraction of it...
most of the control protocols have no authentication built into them either, in fact none of the ones i've worked with. maybe the newer ones do?
there's the attitude: There is always somebody out there smarter than you, and there is always going to be a bug or security vulnerability somewhere in the system.
There was an interesting blog in the economist magazine pondering what else could be done with the 680 billion the US spends annually on defense.
While the US has spent a trillion in Iraq the chinese have spent a trillion improving their infrastructure.
Also, the electronics can supply as much reactive effect as the peak effect of the wind turbines even when the turbines are completely stopped.
can you expand on this? Is it a synchronous machine inside a wind turbine? They can be used as a synchronous condenser to supply reactive power when the turbine is stopped?
What electronics can do this?
power generated locally is worth more too. wholesale prices generators get paid are 3-7 cents /kwh without fancy government contracts while power delivered to a customer's house is worth 20-30 cents/kwh. so while it is expensive to permit and build a big plant, transmission and distribution are also expensive.
shwartz ruined sun
I wonder how verizon would fare if they were able to offer the iPhone with unlimited data as well...
"he story notes that mobile data at AT&T has grown 4,932% over the last 3 years."
3 years ago mobile data traffic was probably nearly zero, so putting this in relative terms means nothing to me.
I wonder how much traffic their feeble network is actually dealing with? Imagine it was only 100 MB/s off each cell site and they are whinging like this...
skype on windows has become a piece of shit! The linux version does everything except for SMS messages and hasn't become a UI nightmare. let's keep it that way
That all depends on your industry/area of research.
ah, i see, it depends on your niche...
thanks
hi,
the device has already shorted out. a short circuit has nearly zero resistance, and thus nearly infinite current will flow. nearly infinity (ok well probably more like 100 Amps) is much larger than 15 or 30 so a short circuit will trip the circuit breaker no matter what it is rated for.
some mobile internet dongles have 2gb flash memory in them that is mounted as a drive for your reading and writing pleasure. sometimes they stick the driver for the dongle on there.
so your mobile internet dongle may be a hard drive as well, hence the usb-storage.
you have just convinced me to upgrade from hardy to karmic. I will be making a partimage first though.
come on now, steel pipes aren't THAT expensive...neither are pumps.
what if they collected the fresh water vapour that is evaporating off the salt water as well?
TFA says they make fresh water by heating salt water with electricity so why not just heat it mostly with the sun and then a bit of electricity.
TFA is a bit light on details: why do Na+ ions go to one stream and CL- to the other? Have they got membranes that are impervious to CL- and NA+?