Global Warming?

[Redneck in training]

In comparison to DC - Yes. ... But for 60Hz; in comparison to much - not much. I also expect that ~ million Volt DC lines and dealing with voltage conversions would be a bigger deal.
larry

HVDCs can transport the same power as HVAC but at lower voltage. The cost effective distance for HVAC is about 2500 miles while HVDC is cost effective up to about 4300 miles.
Thre are DC lines in Sveden, Russia, China, Canada, Brasil and other countries as well.

 

[Redneck in training]

In comparison to DC - Yes. ... But for 60Hz; in comparison to much - not much. I also expect that ~ million Volt DC lines and dealing with voltage conversions would be a bigger deal.
larry

HVDCs can transport the same power as HVAC but at lower voltage. The cost effective distance for HVAC is about 2500 miles while HVDC is cost effective up to about 4300 miles.
There are DC lines in Sweden, Russia, China, Canada, Brazil and other countries as well.

 

[Short Game]

Maybe not "global" warming, but certainly a hotspot:

Flashpoints Daily Newsmag 05-09-12. Dr. Micio Kaku by FLASHPOINTS NEWS MAGAZINE on SoundCloud - Create, record and share your sounds for free

 

[Rob-D]

HVDCs can transport the same power as HVAC but at lower voltage. The cost effective distance for HVAC is about 2500 miles while HVDC is cost effective up to about 4300 miles.
Thre are DC lines in Sveden, Russia, China, Canada, Brasil and other countries as well.

Ladia,
This is interesting to me, when you say "cost effective" can you give us an idea? If the DC voltage is "lower" that means heavier wire, what size wire are we talking about? I thought, correct me if I'm wrong, that the issue is wire size, I know in my small systems here it is often the deciding factor. My intertie runs ~ 400 VDC depending on the number of modules in the line and my off grid runs 48V. 48 is the highest I can run into my MPPT's, axctually the voltage is higher, over 100 volts but the MPPT's max out at 150 volts and module cold temps can reach that here if I string three 24 volt modules in series so we have to run two max.

Rob

 

[Rob-D]

Maybe not "global" warming, but certainly a hotspot:

Flashpoints Daily Newsmag 05-09-12. Dr. Micio Kaku by FLASHPOINTS NEWS MAGAZINE on SoundCloud - Create, record and share your sounds for free

We're building two new reactors in the Atlanta area:

Nuclear agency approves first nuclear reactors since 1978 ? USATODAY.com

 

[mostly_gas]

GE Fanuc Distributor Series 90-70 PLC IC697CPX935 IC697CPX782

The GE Fanuc Series 90-70 was introduced in 1988 as a full functioning PLC system. It utilized the IC697CPU782 processor which soon became the IC697CPX782 CPU. The new processors no longer needs the IC697MEM715, IC697MEM719, IC697MEM731, IC697MEM733 or IC697MEM735 memory modules. The new IC697CMM742 Ethernet controller eliminates the older IC697CMM741.

I never worked on the machines specifically but I know those old servo boards weren't as good as the new stuff.

Still using your 1988 computer?

Do you ever ask a question without trying to bait people? I thought we went through this. If I stop answering your questions don't wonder why.

Rob

I have not baited you rob.
a) wrong control, fanuc 7m was in use in 1979. Thought you implied you knew something about CNC.
b) you said basically electronics don't fail, I provide am example to show that electronics can and do fail.
c) If you could read English and put conversations in context the would be a lot less contention.
d) What does using a old computer do with industrial electronics? Hint in industrial applications electronics are NOT upgraded as often because of the cost or complexity of replacement.

 

[Redneck in training]

Ladia,
This is interesting to me, when you say "cost effective" can you give us an idea? If the DC voltage is "lower" that means heavier wire, what size wire are we talking about? I thought, correct me if I'm wrong, that the issue is wire size, I know in my small systems here it is often the deciding factor. My intertie runs ~ 400 VDC depending on the number of modules in the line and my off grid runs 48V. 48 is the highest I can run into my MPPT's, axctually the voltage is higher, over 100 volts but the MPPT's max out at 150 volts and module cold temps can reach that here if I string three 24 volt modules in series so we have to run two max.

Rob

AC lines suffer skin effect, have leakage through insulation, capacitance and inductance against ground and adjacent conductors and resistive loss (heat). If power factor is less than 1 then the line carries current that will not produce work at destination. DC lines have leakage through the insulation and resistive loss. Since DC lines don't suffer skin effect they can carry larger current via the same conductor as AC or use lower voltage to carry the same power. Since the equipment at the beginning and end of the line is expensive they are economical for longer distances.
In example solar panel has $125 inverter for 250W. That is about 50c/w. At this cost 1GW line would require 500 000 000 investment on each end.

 

[Rob-D]

I have not baited you rob.
a) wrong control, fanuc 7m was in use in 1979. Thought you implied you knew something about CNC.
b) you said basically electronics don't fail, I provide am example to show that electronics can and do fail.
c) If you could read English and put conversations in context the would be a lot less contention.
d) What does using a old computer do with industrial electronics? Hint in industrial applications electronics are NOT upgraded as often because of the cost or complexity of replacement.

Oh , let's see, I don't know about CNC used over 30 years ago so I don't know anything about CNC?

You want to compare the electronics from 30 years ago to the electronics of today? Are you kidding? Let me ask you what you know about electronics?
Whose chip would you use for a 3 amp CNC stepper control application. Would you use a servo controlled closed loop or a stepper open loop? How about the power supply design for that application? What frequency would you use for the SMPS supply? Whose high side MOSFETS would you use for that and how would you develop the charge pump gate drive for those or would you use 'P' type MOSFETS or HEXFETS instead? How would you address 'shoot through' on the CNC supply?

Hint, electronics TODAY are upgraded more often because it is cost effective to do so. Thirty years ago home computers weren't updated as often as today either.

Today you can buy CNC for a fraction of its cost 30 years ago. Today I have a small CNC in my lab to drill PCBs, how about you? Do you have a CNC in your lab? Whose program do you use to run it? Do you even have a lathe in your lab? I have several, would you like to talk about ceramic cutter applications for different materials? Speeds and feeds? CNC welding, plasma cutting applications of CNC?

Rob

 

[Rob-D]

AC lines suffer skin effect, have leakage through insulation, capacitance and inductance against ground and adjacent conductors and resistive loss (heat). If power factor is less than 1 then the line carries current that will not produce work at destination. DC lines have leakage through the insulation and resistive loss. Since DC lines don't suffer skin effect they can carry larger current via the same conductor as AC or use lower voltage to carry the same power. Since the equipment at the beginning and end of the line is expensive they are economical for longer distances.
In example solar panel has $125 inverter for 250W. That is about 50c/w. At this cost 1GW line would require 500 000 000 investment on each end.

Ladia
An inverter converts DC to AC or visa versa, I'm not sure I see your example. A PV module puts out DC, we can string (series) PV modules to very high voltages, in fact this is how my intertie works. Micro converters maximize the DC (MPPT) from each module and then each module is added to the next. The total DC is ~400V give or take the amount of light hitting the panel. In this case we only have to invert the DC to AC to accommodate the grid.

Rob

 

[Redneck in training]

Ladia
An inverter converts DC to AC or visa versa, I'm not sure I see your example. A PV module puts out DC, we can string (series) PV modules to very high voltages, in fact this is how my intertie works. Micro converters maximize the DC (MPPT) from each module and then each module is added to the next. The total DC is ~400V give or take the amount of light hitting the panel. In this case we only have to invert the DC to AC to accommodate the grid.

Rob

I understand the advantage of distributed power generation and its effect on reliability of the grid. Nevertheless (perhaps until home energy generation become wide spread) there is still need for transfer of energy over long distances. Since HVDC have lower losses than HVAC transmission lines it could be used for such purpose. In example line from east to west could take advantage of the fact that there is four hours difference between the coasts.
Coal burning power units have relatively small turn-down ratio. Typical lignite burning boiler has to be stabilized with oil or gas under 90% of rated power. That is why we have street lights to provide load on the generators at night when the demand is otherwise low. It would be advantageous to move energy from west coast to east coast in the morning and the other way around in the evening.