4 Wire Wye Vs 4 Wire Delta - New Construction

[ggunn]

I don't mind government funded R&D that becomes public knowledge. Can't say the same for production subsidies. Skews the economics to where we get wind farms where the $/kw are a complete joke. And the joke is on us that pay the taxes.

I have a terrifying picture of a bureaucratic committee judiciously applying their well thought out strategy. (shudder) Quoting Ronald Reagan:

The most terrifying words in the English language are: I'm from the government and I'm here to help.

Government's view of the economy could be summed up in a few short phrases: If it moves, tax it. If it keeps moving, regulate it. And if it stops moving, subsidize it.​

ice

Reagan. Trickle down economics. Bah.

 

[mbrooke]

Sounds great. What kind of time frame do you have in mind? I'm thinking a 100+years?

How about this:
15 years: Room temp superconductors in transmission use
25 years: Fusion plants on line
50 years: Cold fusion plants on line
100 years: Distribution is by beamed power

Yep, we will have to scrap all the distribution lines. Think of all the massive copper we can recycle

ice

Over a 100 year period, but in the next 30 HVDC will be the norm in many places.

 

[iceworm]

Reagan. Trickle down economics. Bah.

Uh-Oh. Shame on me for mentioning a taboo. No more politics now. We wouldn't want a super-powered mega moderator, .........

aggg.... I can feel the ..... throat constricting ....

 

[ggunn]

Uh-Oh. Shame on me for mentioning a taboo. No more politics now. We wouldn't want a super-powered mega moderator, .........

aggg.... I can feel the ..... throat constricting ....

Me, too. Peace.

 

[Besoeker]

Technically there is no such thing as an electronic transformer either, but that name is applied frequently

If you consider the transformation just to be transforming from one voltage to another it can be, and has been done electronically.
We made quite a few DC variable speed drives where the incoming fixed DC was changed to 0-Vmax. It was entirely (power) electronics. And, where required, the current flow was reversible. These were not toys or on the scale of wall warts but for DC motors upwards of 100kW.

The push for DC in utilization will only come from solar panels where maximum efficiency is obtained by bypassing inverters. Imagine feeding a 120 volt DC solar system into an ultra capacitor or super battery then being able to deliver that right to a receptacle, lighting circuit or directly out to the grid via simple protective device (separates system on loss of POCO) rather then energy wasting inverters.

The output of solar PV is variable depending on the level of insolation. If you wanted to operate something rated at 120Vdc, you still need a voltage regulator. And probably one configured for both buck and boost.
Directly to a receptacle....hmmm........pull the plug out and draw an arc a foot long. You could turn off the power to the item first - but only if the on/of switch is capable of doing so. Which is highly unlikely without special design.

In short, the power grid of tomorrow will allow all customers in all locations to add or deduct as much power as they like from the grid with minimal losses and exceptional reliability.

The grid is not likely at domestic/commercial voltages. It would really have to be at a very much higher voltage. So then you would need a bidirectional DC-DC converter. And, for safety reasons, galvanic isolation. All with losses. Directly from/to the grid? Don't think so.

I'm not suggesting that your ideas are impossible to achieve technically. But of dubious merit, if any, for practical implementation.

 

[mbrooke]

If you consider the transformation just to be transforming from one voltage to another it can be, and has been done electronically.
We made quite a few DC variable speed drives where the incoming fixed DC was changed to 0-Vmax. It was entirely (power) electronics. And, where required, the current flow was reversible. These were not toys or on the scale of wall warts but for DC motors upwards of 100kW.

The tech is being proven everyday. As I said, the amount of appliances, machines, tools, controls, ect that convert AC to DC only to change it back to AC is staggering. Seems like a lot of trouble when AC is already there?

The output of solar PV is variable depending on the level of insolation. If you wanted to operate something rated at 120Vdc, you still need a voltage regulator.

Nope, just a 120 volt rated battery bank. The PV is just the source for the battery charger. Think electrical substations with a DC battery bank. Minus the fuse most loads are directly fed off them be it 12, 24, 90 ect volts. Chargers keeps the battery bank full and cutoff when full.

And probably one configured for both buck and boost.

Not required.

Directly to a receptacle....hmmm........pull the plug out and draw an arc a foot long. You could turn off the power to the item first - but only if the on/of switch is capable of doing so. Which is highly unlikely without special design.

This is a legit concern that needs to be addressed before DC takes over. But I doubt no solution would ever be found.

The grid is not likely at domestic/commercial voltages. It would really have to be at a very much higher voltage. So then you would need a bidirectional DC-DC converter.

Of course, this is why I mention them. Before a home is fed by 90, 120, 180, 250 or which ever voltage it will be stepped down via converter from 15kv (or other decided upon MV voltage) DC.

And, for safety reasons, galvanic isolation.

Of course, the only coupling between the converter's transformer will be an opti-coupler. No electrical connection will exits much like most laptop chargers.

All with losses. Directly from/to the grid? Don't think so.

If losses are so high with transformers we would not have 50/60Hz transformers stepping 7.2kv down to 120/240 or 11kv down to 240/415 in the UK. If you mean the electronics within the converter will have losses of course it will, but that doesnt slow down modern day electronic transformers, lighting ballasts. ect.

I'm not suggesting that your ideas are impossible to achieve technically. But of dubious merit, if any, for practical implementation.

Its far from impractical. 1/4 is already in place today increasing every day.

 

[Besoeker]

The tech is being proven everyday. As I said, the amount of appliances, machines, tools, controls, ect that convert AC to DC only to change it back to AC is staggering. Seems like a lot of trouble when AC is already there?

The technology is already there. By the bucket load. VFDs are a prime example where DC is produced by rectifying AC. The resultant DC is then inverted to give an AC output.

Nope, just a 120 volt rated battery bank.

How would you cope with the variable output of the PV array? What if it drops below 120V? What if it exceeds 120V? The 120V battery has quite a low impedance. I can't see this working without a regulator of some sort. The battery charger in a UPS system for example is regulated.

Not required.

I disagree for the reasons above

This is a legit concern that needs to be addressed before DC takes over. But I doubt no solution would ever be found.

You can switch DC of course. On the DC variable speed drives I mentioned earlier we do but it needs a very large bar and shaft contactor as opposed to the typical block contactor you would use in an AC drive. Over and above, we include interlocks to ensure that the contacts don't have to break current. But they are rated to do so if such need arises.

For domestic applications, none of the existing switches and receptacles would be suitable for DC operation. All the light switches would have to be changed. Receptacles would probably need to have some kind of mechanism to trap the plugs until the power is removed. Appliances would have to come with plugs to be compatible with the new receptacles. Think about the scale of that. And I'm sure there would be a host of other issues that I haven't thought of to contend with

Of course, this is why I mention them. Before a home is fed by 90, 120, 180, 250 or which ever voltage it will be stepped down via converter from 15kv (or other decided upon MV voltage) DC.

Of course, the only coupling between the converter's transformer will be an opti-coupler. No electrical connection will exits much like most laptop chargers.

Two for the price of one here.
For domestic, you'd be looking at maybe 20kW. A 20kW opto coupler?
And how would you deal with a 6,600kW gas compressor. Via an opto coupler?

If losses are so high with transformers we would not have 50/60Hz transformers stepping 7.2kv down to 120/240 or 11kv down to 240/415 in the UK.

Losses are not so high in transformers in distribution systems. Typically around 2% at full rating.

Its far from impractical. 1/4 is already in place today increasing every day.

One quarter of what exactly?

As I said, whilst technically not beyond what can be done but I have a feeling you really don't grasp the scale.

 

[iceworm]

mb -
Your enthusiasm is great. I'm all for it.

Truth - not facetious:
I think we will need the beamed power to impliment the opto isolation. But that is okay. It will show up with the DC breakers and the 100x energy density batteries.


And we will still have to find a household sized (edit to add) cost effective renewable.

Q: what percentage of power is used by residential as compared to medium/heavy industry?

One of my customers uses 10MW, 24/7. That's 8760 x 10 x 10^3 KWH/year. Call it 100 x 10^6 kwh/year. As industry goes - that's not very heavy.

ice

Residential users are numerous but they don't use much power. Industry is few in number, but maybe the largest consumers (and I don't know this). So, the question is: How does your plan take care of the industrial user?

 

[iceworm]

The technology is already there. By the bucket load. ...

How would you cope with the variable output of the PV array?....

For domestic applications, none of the existing switches and receptacles would be suitable for DC operation. ...

Appliances would have to come with plugs to be compatible with the new receptacles. Think about the scale of that. ...

For domestic, you'd be looking at maybe 20kW. A 20kW opto coupler? ...

And how would you deal with a 6,600kW gas compressor. Via an opto coupler? ...

As I said, whilst technically not beyond what can be done but I have a feeling you really don't grasp the scale.

Bes -
Grasp the scale? - likely not. Really doesn't matter. These are all just engineering issues.

To quote my kid at the third grade science fair (years back): He had build a battery using lemons, carbon rods, galvanized nails. Took two in series to barely light a little led. Had to use a paper towel tube to see it in a bright room. I didn't hear this, but one of the instructors told me about it later.

Judge: Not very bright is it?
Kid: Getting it to light at all is physics. Lighting up a city is engineering.

It's not an original - he read it somewhere. Still he got the concept correct.

All the things you bring up are just engineering.

mb is discussing global concepts. Picking at the engineering issues don't change any of this. What direction will we humans head? Don't know. It won't necessarily follow mb's or my vision. I think it will follow the money. But it won't be limited by the engineering hard spots.

The Vision per the worm

 

[iceworm]

Bes - Added thought
One of the reasons they eventually throw us dynosars out and let the kids take over is cause the kids aren't stuck on what can't be done.

 

[Besoeker]

Bes - Added thought
One of the reasons they eventually throw us dynosars out and let the kids take over is cause the kids aren't stuck on what can't be done.

I did point out a couple of times, it isn't technically beyond what can be done. Perhaps that should be could be done.

 

[mbrooke]

mb -
Your enthusiasm is great. I'm all for it.

Thanks

Truth - not facetious:
I think we will need the beamed power to impliment the opto isolation. But that is okay. It will show up with the DC breakers and the 100x energy density batteries.

I think you misunderstood:

https://en.wikipedia.org/wiki/Opto-isolator


https://www.google.com/search?q=opt...ved=0ahUKEwi2nLL_6bPJAhUOz2MKHZh_BI4Q_AUIBygC

This device will allow secondary feed back to the primary side converter logic without electrically connecting the two which is a big advantage when 15kv power is being stepped down to 120 volts.

Further I can see this also being used to fire the thrysistors. The control will be LV (say 100 volts) with LEDs beaming light up through a fiber optic cable into HV IGBTs. This way full inversion of the primary can be achieved with complete isolation. No expensive MV electronics with full user safety. Much like a pole mounted recloser control, the box is all 120 volts operating LV motors and solenoids to open and close a 15kv circuit.

And we will still have to find a household sized (edit to add) cost effective renewable.

Q: what percentage of power is used by residential as compared to medium/heavy industry?

One of my customers uses 10MW, 24/7. That's 8760 x 10 x 10^3 KWH/year. Call it 100 x 10^6 kwh/year. As industry goes - that's not very heavy.

The price of solar will go down. We are already seeing more and more grid tied inverters. Yes a single home is not much, but on a hot day a 60MVA substation can easily have 25MVA of residential in some towns. As is mose distribution feeders by customer type ratio are about 60% resi.

ice

Residential users are numerous but they don't use much power. Industry is few in number, but maybe the largest consumers (and I don't know this). So, the question is: How does your plan take care of the industrial user?

Much like the resi user, they can by or sell power to the grid economically no issue.

 

[mbrooke]

The technology is already there. By the bucket load. VFDs are a prime example where DC is produced by rectifying AC. The resultant DC is then inverted to give an AC output.

Exactly my point. Does a VFD care if the utility power coming in is DC?

How would you cope with the variable output of the PV array? What if it drops below 120V? What if it exceeds 120V? The 120V battery has quite a low impedance. I can't see this working without a regulator of some sort. The battery charger in a UPS system for example is regulated.

How is it done today when a PV array is charging a battery bank?

You can switch DC of course. On the DC variable speed drives I mentioned earlier we do but it needs a very large bar and shaft contactor as opposed to the typical block contactor you would use in an AC drive. Over and above, we include interlocks to ensure that the contacts don't have to break current. But they are rated to do so if such need arises.

For domestic applications, none of the existing switches and receptacles would be suitable for DC operation. All the light switches would have to be changed. Receptacles would probably need to have some kind of mechanism to trap the plugs until the power is removed. Appliances would have to come with plugs to be compatible with the new receptacles. Think about the scale of that. And I'm sure there would be a host of other issues that I haven't thought of to contend with

Correct, which is why it will be done last.

As for the receptacles I could guess anything, but chances are the end product will do its task with little if any compromise.

Two for the price of one here.
For domestic, you'd be looking at maybe 20kW. A 20kW opto coupler?
And how would you deal with a 6,600kW gas compressor. Via an opto coupler?

Nope, a single 4 watt unit will do. We only need the primary computer logic to know how the secondary of the converter is doing.

A real world example of an opti coupler (U1) at work, typical for most computer/cell phone chargers as seen here:


http://powersupply33.com/wp-content/uploads/2011/07/60-Watt-Laptop-battery-charger.jpg

Losses are not so high in transformers in distribution systems. Typically around 2% at full rating.

And possibly less for DC to DC conversion. Getting more efficiency out of a kHZ transformer is nothing.

One quarter of what exactly?

Everything. Generation to utilization. HVDC projects are popping up and expanding all over the world with consumer electronics/appliances nearly all having inverters built into them. That is still only part of it, wind, solar, biogas, micro-turbines are all or can be related to DC in some way.

As I said, whilst technically not beyond what can be done but I have a feeling you really don't grasp the scale.

I get the scale, but I have a feeling you dont grasp where fate is driving this.

 

[mbrooke]

Bes -
Grasp the scale? - likely not. Really doesn't matter. These are all just engineering issues.

To quote my kid at the third grade science fair (years back): He had build a battery using lemons, carbon rods, galvanized nails. Took two in series to barely light a little led. Had to use a paper towel tube to see it in a bright room. I didn't hear this, but one of the instructors told me about it later.

Judge: Not very bright is it?
Kid: Getting it to light at all is physics. Lighting up a city is engineering.

It's not an original - he read it somewhere. Still he got the concept correct.

All the things you bring up are just engineering.

mb is discussing global concepts. Picking at the engineering issues don't change any of this. What direction will we humans head? Don't know. It won't necessarily follow mb's or my vision. I think it will follow the money. But it won't be limited by the engineering hard spots.

The Vision per the worm

Personally the vast majority of people around students belong in prison. People who have no clue that they have no clue. They denigrate, belittle and ridicule the very people who created all the luxury that surrounds them which they have to yet fully appreciate. :happyno:

 

[ggunn]

Personally the vast majority of people around students belong in prison. People who have no clue that they have no clue. They denigrate, belittle and ridicule the very people who created all the luxury that surrounds them which they have to yet fully appreciate. :happyno:

Good grief!! Where did you go to school?? I attended a LOT of college classes (I have a BSEE and a BSChem) and I never saw or heard anything remotely like what you are describing. Not in grade school or high school, either.

 

[mbrooke]

Good grief!! Where did you go to school?? I attended a LOT of college classes (I have a BSEE and a BSChem) and I never saw or heard anything remotely like what you are describing. Not in grade school or high school, either.

Id say you were lucky then. Public education is not what it once was. :happyno:

 

[kwired]

Id say you were lucky then. Public education is not what it once was. :happyno:

Is still better in most small communities however, content being taught maybe not as good as once was, but students get more individual attention from teachers then at large schools, social events at the school usually include everyone - which is good where at big schools many are left out of a lot of things whether intentional or not.

 

[ggunn]

Id say you were lucky then. Public education is not what it once was.

Yeah, right. My daughter attended public school and she turned out just fine, too, and I knew all her teachers. I'll agree that there are bad apples in every barrel, but your sweeping condemnation of educators is way off in the weeds. Pray tell, where did you get the data upon which you based that opinion?

 

[Besoeker]

Exactly my point. Does a VFD care if the utility power coming in is DC?

Indeed. We have made VFI systems that use a common DC input bus.
But I think kyou miss or misunderstood my point. It isn't being proven as you suggest. It already has been.

How is it done today when a PV array is charging a battery bank?

And a charge controller.
Here's the first link I found. No doubt there are others.
http://www.solarjourneyusa.com/learn-buy-equipment.php#drawarray

Correct, which is why it will be done last.

It's exactly why it might not.

As for the receptacles I could guess anything, but chances are the end product will do its task with little if any compromise.

Nail on head. End product. It would need all existing units to be ripped out and replaced with something much larger, more complex, and much more expensive.

I don't know how much you've played around with DC on any significant scale. I've designed and installed systems up to 40,000Adc. Others up to a few thousand volts. Some water cooled, some force air cooled, some air natural. They were all specialist applications that really needed DC. I can promise you that DC is an entirely different beast. And I intentionally used that word.

A little salutary tale.
We did a converter for the VSOE, the Orient Express. It was a resurrection of that one made famous by Agatha Christie in "Murder on the Orient Express".As I said, A luxury train that crossed several European countries. The input had to cope with all the frequencies and voltages on the line between countries. Including 3000Vdc.
It was tested in the railway lab in Vitry on the outskirts of Paris. At 3000Vdc, a fault was simulated. At the time, we couldn't get 3000Vdc rated semiconductor fuses so we put three 3kV AC fuses in series.

Big mistake. They didn't clear the fault and ended up as a molten mass in the bottom of the enclosure.
As I said, DC is an entirely different beast and demands a different level of respect.

Nope, a single 4 watt unit will do.

Really?? For a gas compressor rated at 6,600kW? About 9,000hp.

A real world example of an opti coupler (U1) at work, typical for most computer/cell phone chargers as seen here:
http://powersupply33.com/wp-content/uploads/2011/07/60-Watt-Laptop-battery-charger.jpg

But my cell phone, monitor, laptop, printer, camera charger, Kindle, DVD player, Blackberry, and various battery operated power tools need different voltages. So you would still need different voltage converters for each.

And possibly less for DC to DC conversion. Getting more efficiency out of a kHZ transformer is nothing.

And possibly not.

Everything. Generation to utilization. HVDC projects are popping up and expanding all over the world with consumer electronics/appliances nearly all having inverters built into them.

I don't think my laptop has a built in inverter. Nor my printer, cell phone........etc.

I get the scale,

With respect, I don't think you do.

 

[mbrooke]

Yeah, right. My daughter attended public school and she turned out just fine, too, and I knew all her teachers. I'll agree that there are bad apples in every barrel, but your sweeping condemnation of educators is way off in the weeds. Pray tell, where did you get the data upon which you based that opinion?

Not everyone has the same experience. Ive seen and heard enough to reach my own opinion. Telling me education is just fine is like telling an Iraq or Vietnam veteran war is puppies and unicorns.