Some Solar problems ahead?

TonyS wrote:

On second thought I got a bit of an idea where the problem may come to
surface. I have no experience in grid technology, so correct me if I am
wrong.

First of all I must say, people do try to avoid heavy usage when the sun
is shining, cause they can sell their electricity for about double of
what they would pay. Which means they do feed into the net as much as
they can in day time.
Not really, or at least, they don't have any say in that.

In the following hypothetical, (I'm assuming that ALL homes on a given
isolated grid, also have solar assistance). It won't happen in real
life, but this is just for the sake of this explanation.

If ONE home chooses to stop using ALL possible power during a peak
demand interval, AND, no-one else does that, THEN, their system has the
*potential* (owing to light and battery power availability) to supply
its full capability into the grid, and get paid for their bit.
This is of course assuming the remaining homes have a net negative
generation, that is, even accounting for THEIR own solar systems, they
still use MORE than what they generate themselves. In other words, they
still draw something from the grid.

If ALL solar homes had the same idea (power off everything and let
their solar systems pump power into the grid), then, NO-ONE would
pumping power into the grid - their controllers simply will NOT let it.
There are safety limits built in that prevent over voltage from
happening. This entirely debunks the "solar overloads the wiring"
statement, as well as the amount of copper.

The voltage at a transformer would always be at the higher end to cater
for the copper losses to be expected farther down the line.
It depends. Although the "grid" operates as a large-scale entity, it
does indeed have some localised effects. And it NEEDS this, because
even though the "grid" operates with some self-regulation as far as
voltage goes (power stations vary up and down according to demand, and
voltage is a good indicator of what the load is.
There are quite high variations on the local level, because one suburb
may have no air-cons, and the next door suburb may have them all. And
the larger scale grid feeds them both.
To ensure YOUR grid voltage stays within "acceptable" limits, there
are local transformers that change taps to offer some control for this.

In the hypothetical that solar systems feed "too much" power into the
grid (they won't, but let's say they do anyway), the transformer will
switch to account for that, so less comes from the larger scale grid,
and the local solars can supply a chunk of power.

This will not magically "stress" the copper, because the copper isn't
carrying any more current that it's capable of ANYWAY.

If, however, there are a number of powerful solar supplies feeding in
along that transmission line, much of the current goes the other way,
Firstly, there is no "other way". Due to normal losses in copper,
YOUR solar system has MOST effect closest to you, and the LEAST effect
furthest away from you. The change YOUR solar box has on the whole is
rather local.

and the voltage drop due to copper losses could even ADD to the grid
voltage.
Again, only locally, AND if the box lets it. If the grid voltage is
ALREADY high, YOUR system will NOT push bucketloads of power into the grid.

So instead of the usual voltage drop due to copper losses we
would have a gain. The only way to avoid this reversal would be to use
more copper or less solar.
:) Congratulations, you've just turned a positive into a negative.
What you're saying is a GOOD thing, and does not require "fixing". It's
also the cheapest and most effective way of addressing load.

Take the far southern end of Victoria for instance. They're at the
end of a long copper line, ant the wrong end of the power generation
side, so there are significant losses. They have increasing peaks loads
due to air cons and huge TV sets.
Increasing copper would help, but ultimately, no-one is going to pay
millions so a tiny town can have air cons and TV sets.
What they're doing now, is using wind power to supplement peak power.
So that droop due to load goes away, because the wind generators are
taking up the slack. This is a GOOD thing.
Of course, they want to whine about the noise, and they have every
right to do that. The easiest way to fix that is to get THEM and THEM
ALONE to pay the millions or billions for the copper upgrades. As long
as everyone else doesn't have to pay, I'm quite happy to let them have that.

As far as fluctuations are concerned, I think we'd need a lot more solar
power, like a double digit share, to see an impact on the grid voltage
or frequency.
That theory would fail, mainly because it's these huge peaks (aircons)
that need LOTS of power generation over short periods.
Generating this class of power is expensive, but in above example,
it's still cheaper than copper.
Again, this is for long haul copper, local systems will see no
(worthwhile) gain in copper upgrades.
--
RAID Antivirus - Kills Virus's DEAD!!!
 
On 15/10/2011 6:23 PM, John Tserkezis wrote:
TonyS wrote:
[---]

Which means they do feed into the net as much as
they can in day time.

Not really, or at least, they don't have any say in that.

I meant they don't do the washing or run the pool.
With a 2KW system, he fridge and smaller stuff draws 1 or 2 amps.
6 amps will be fed in the grid.

In the following hypothetical, (I'm assuming that ALL homes on a given
isolated grid, also have solar assistance). It won't happen in real
life, but this is just for the sake of this explanation.

If ONE home chooses to stop using ALL possible power during a peak
demand interval, AND, no-one else does that, THEN, their system has the
*potential* (owing to light and battery power availability) to supply
its full capability into the grid, and get paid for their bit.
This is of course assuming the remaining homes have a net negative
generation, that is, even accounting for THEIR own solar systems, they
still use MORE than what they generate themselves. In other words, they
still draw something from the grid.

If ALL solar homes had the same idea (power off everything and let their
solar systems pump power into the grid), then, NO-ONE would pumping
power into the grid - their controllers simply will NOT let it.
There are safety limits built in that prevent over voltage from
happening. This entirely debunks the "solar overloads the wiring"
statement, as well as the amount of copper.
I don't see the point of the assumption. There will always be a number
of houses with PV producing more than they use, especially on days where
no A/C is needed. The line loss will lift the voltage.
Should the upper voltage limit be reached, some of the inverters will
cut out first and the voltage will not rise above he limit. But,
depending on the hysteresis of the sensing circuits, they will switch on
again. An inverter that switches off turns into a sink what used to be a
source and so not only takes away feeding current but also adds some
load and so amplifyies the effect. Depending on a lot of factors and
inverter design I could imagine some oscillation happening here.
Modelling this situation is difficult and we will wait and see if it can
happen.
In any case, it's not good as a switched off inverted defeats the
purpose of the PV system and oscillations, God knows...
The voltage at a transformer would always be at the higher end to cater
for the copper losses to be expected farther down the line.

It depends. Although the "grid" operates as a large-scale entity, it
does indeed have some localised effects. And it NEEDS this, because even
though the "grid" operates with some self-regulation as far as voltage
goes (power stations vary up and down according to demand, and voltage
is a good indicator of what the load is.
There are quite high variations on the local level, because one suburb
may have no air-cons, and the next door suburb may have them all. And
the larger scale grid feeds them both.
To ensure YOUR grid voltage stays within "acceptable" limits, there are
local transformers that change taps to offer some control for this.
Never knew that. Are those solid state switches?

In the hypothetical that solar systems feed "too much" power into the
grid (they won't, but let's say they do anyway), the transformer will
switch to account for that, so less comes from the larger scale grid,
and the local solars can supply a chunk of power.

This will not magically "stress" the copper, because the copper isn't
carrying any more current that it's capable of ANYWAY.

If, however, there are a number of powerful solar supplies feeding in
along that transmission line, much of the current goes the other way,

Firstly, there is no "other way". Due to normal losses in copper, YOUR
solar system has MOST effect closest to you, and the LEAST effect
furthest away from you. The change YOUR solar box has on the whole is
rather local.
I don't doubt that but I think in the article the assumption was that
too many PVs are feeding. If you got more sources than sinks the net
effect is source, with the above mentioned possible effects.

and the voltage drop due to copper losses could even ADD to the grid
voltage.

Again, only locally, AND if the box lets it. If the grid voltage is
ALREADY high, YOUR system will NOT push bucketloads of power into the grid.

So instead of the usual voltage drop due to copper losses we
would have a gain. The only way to avoid this reversal would be to use
more copper or less solar.

:) Congratulations, you've just turned a positive into a negative. What
you're saying is a GOOD thing, and does not require "fixing". It's also
the cheapest and most effective way of addressing load.
Well the downside is, if PVs switch off and assuming nothing else bad
happens, the investment would still be a waste of money (taxpayers money
too). The owners might not even notice, only wonder why the power bill
doesn't go down!

Take the far southern end of Victoria for instance. They're at the end
of a long copper line, ant the wrong end of the power generation side,
so there are significant losses. They have increasing peaks loads due to
air cons and huge TV sets.
Increasing copper would help, but ultimately, no-one is going to pay
millions so a tiny town can have air cons and TV sets.
What they're doing now, is using wind power to supplement peak power. So
that droop due to load goes away, because the wind generators are taking
up the slack. This is a GOOD thing.
Of course, they want to whine about the noise, and they have every right
to do that. The easiest way to fix that is to get THEM and THEM ALONE to
pay the millions or billions for the copper upgrades. As long as
everyone else doesn't have to pay, I'm quite happy to let them have that.

Why not through in a few smaller nuclear plants :)

As far as fluctuations are concerned, I think we'd need a lot more solar
power, like a double digit share, to see an impact on the grid voltage
or frequency.
What I meant was that sudden solar PV changes won't cause problems at
the generator side yet, due to the small scale.

That theory would fail, mainly because it's these huge peaks (aircons)
that need LOTS of power generation over short periods.
Generating this class of power is expensive, but in above example, it's
still cheaper than copper.
Again, this is for long haul copper, local systems will see no
(worthwhile) gain in copper upgrades.
 
TonyS wrote:

There's a few misconceptions here, I'll address them individually.

I don't see the point of the assumption. There will always be a number
of houses with PV producing more than they use, especially on days where
no A/C is needed.
Yes, my hypothetical examples where the extremes, and only for the
purposes of explanation.

The line loss will lift the voltage.
Yes, but there are limits were it'll no longer supply power to the grid.

Should the upper voltage limit be reached, some of the inverters will
cut out first and the voltage will not rise above he limit.
There are no "cut outs". It's a sliding scale, it could put full
power into the grid, it could put in a couple of amps, it could be less.
It's not an on/off arrangement.

But, depending on the hysteresis of the sensing circuits, they will switch on again.
As above, it's not like that.

An inverter that switches off turns into a sink what used to be a
source and so not only takes away feeding current but also adds some
load and so amplifyies the effect.
No, that doesn't happen either. The controller doesn't take from the
grid any more than it needs to self-manage, and it's not a lot.
If you have flat batteries and no sun, the batteries stay flat.

Depending on a lot of factors and
inverter design I could imagine some oscillation happening here.
None of that either. You're using faulty assumptions.

Modelling this situation is difficult and we will wait and see if it can
happen.
It hasn't, it isn't, and it won't.

In any case, it's not good as a switched off inverted defeats the
purpose of the PV system and oscillations, God knows...
Not even then. It never behaves as an inverter that you may be
familiar with. In case of a blackout, the system shuts down and does
nothing (same under brown-out conditions too). You may have fully
charged batteries in a fucking stinking hot day, and you STILL won't
have any power to charge your phone.

To ensure YOUR grid voltage stays within "acceptable" limits, there are
local transformers that change taps to offer some control for this.

Never knew that. Are those solid state switches?
Relays, I've out of that game for a long time so I'm not sure if
things have changed, but it appears the major changes are around *when*
the taps are changed, rather than *how*.

I don't doubt that but I think in the article the assumption was that
too many PVs are feeding. If you got more sources than sinks the net
effect is source, with the above mentioned possible effects.
And that's where the article fails. If EVERY person on the planet was
connected to the grid AND had a solar setup, then the ONLY difference
you'd notice compared to the current state of affairs is the Return On
Investment time.
Each person would be feeding a LOT less from their PV setups into the
grid.
There would be no cable issues (actually, in some cases it would
IMPROVE the heavy loading issues).
The result would be nothing else than everyone paying lots of money
for, well, very little.

And I say the above because grid supplied power (baseline is coal) is
significantly cheaper than solar.

Well the downside is, if PVs switch off and assuming nothing else bad
happens, the investment would still be a waste of money (taxpayers money
too). The owners might not even notice, only wonder why the power bill
doesn't go down!
Ah, well done. :) You've picked that up.

What I meant was that sudden solar PV changes won't cause problems at
the generator side yet, due to the small scale.
As I've said, they don't do changes like that, it's a sliding scale,
there is nothing abrubt about it.

--
Living poor is best left to those with no money.
 
On 13/10/2011 3:06 PM, Phil Allison wrote:
"Trevor Wilson"


http://www.theaustralian.com.au/national-affairs/carbon-plan/rooftop-solar-panels-overloading-electricity-grid/story-fn99tjf2-1226165360822

**Care to explain how grid connected inverters are capable of feeding MORE
than mains Voltage (whether it is a nominal 230VAC or 240VAC) into the
grid?


** No current would flow from the inverter UNLESS it put out more volts than
were otherwise on the incoming line.
Not true in AC system. In an AC power system, real power flow is
determined by the load angle between the generator and the load. Voltage
level differences determines reactive power flow. Quite possible to have
a generator (invertor) supplying real power, but absorbing reactive power.

David
 
On 16/10/2011 4:30 PM, John Tserkezis wrote:
TonyS wrote:
[ cut]
Should the upper voltage limit be reached, some of the inverters will
cut out first and the voltage will not rise above he limit.

There are no "cut outs". It's a sliding scale, it could put full power
into the grid, it could put in a couple of amps, it could be less. It's
not an on/off arrangement.
There we go, you just demolished my theory,
as well as the statements of Mr.Hart and the power companies.:)

[snipped]

Not even then. It never behaves as an inverter that you may be familiar
with. In case of a blackout, the system shuts down and does nothing
(same under brown-out conditions too). You may have fully charged
batteries in a fucking stinking hot day, and you STILL won't have any
power to charge your phone.

To ensure YOUR grid voltage stays within "acceptable" limits, there are
local transformers that change taps to offer some control for this.

Never knew that. Are those solid state switches?

Relays, I've out of that game for a long time so I'm not sure if things
have changed, but it appears the major changes are around *when* the
taps are changed, rather than *how*.

I don't doubt that but I think in the article the assumption was that
too many PVs are feeding. If you got more sources than sinks the net
effect is source, with the above mentioned possible effects.

And that's where the article fails. If EVERY person on the planet was
connected to the grid AND had a solar setup, then the ONLY difference
you'd notice compared to the current state of affairs is the Return On
Investment time.
Each person would be feeding a LOT less from their PV setups into the grid.
There would be no cable issues (actually, in some cases it would IMPROVE
the heavy loading issues).
The result would be nothing else than everyone paying lots of money for,
well, very little.

And I say the above because grid supplied power (baseline is coal) is
significantly cheaper than solar.

Well the downside is, if PVs switch off and assuming nothing else bad
happens, the investment would still be a waste of money (taxpayers money
too). The owners might not even notice, only wonder why the power bill
doesn't go down!

Ah, well done. :) You've picked that up.

What I meant was that sudden solar PV changes won't cause problems at
the generator side yet, due to the small scale.

As I've said, they don't do changes like that, it's a sliding scale,
there is nothing abrubt about it.
So the "tripping out" jargon and in fact most of the article
(http://www.theaustralian.com.au/national-affairs/carbon-plan/rooftop-solar-panels-overloading-electricity-grid/story-fn99tjf2-1226165360822)
is not telling the truth:


*"Mr Hart, who owns EcoSouth Solar Electricity, said areas with a lot of
solar panels pushed the voltage up to the maximum allowable level,
triggering shutdowns in the individual systems and taking the load off
the grid.

He said solar systems "drop out for a few minutes" when voltages get too
high, a phenomenon known as "tripping out".

"Then they try to come online again and it pushes the voltage up again
and it's very wearing," he said. "That's the problem with having too
much solar in an area where the local authority hasn't got enough wires
or copper in the street to hold the voltage down."*


The truth would be that with more solar rooftop PV we are not facing
instability but inefficiency (in top of the inefficiency caused by the
power plants running on lower load).

*Mr Hart said the size of conductors and cables in the streets would
have to be upgraded "so it can handle lots of solar, versus times when
there's lots of load and no solar".*

That's true then, more copper could fix the problem. Obviously no one
wants to pay for that.

Another way would be to monitor the PV installations locally in detail
and not approve new ones unless the lines have been upgraded.
See the last paragraph of the article:


*"In Western Australia, Horizon Power has set "hosting capacity limits"
for renewable energy installations."*

I wonder if there could be some other reasons as well....
 
"David is a trolling Fake "

**Care to explain how grid connected inverters are capable of feeding
MORE
than mains Voltage (whether it is a nominal 230VAC or 240VAC) into the
grid?


** No current would flow from the inverter UNLESS it put out more volts
than
were otherwise on the incoming line.


Not true in AC system.

** The topic is domestic premises where load current is normally very close
to being in-phase - and that current exists in the conductors feeding each
premises.

The feed conductors are essentially resistors at 50Hz.

So voltage drop determines the direction of flow.

You fucking tenth with moron.



In an AC power system, real power flow is determined by the load angle
between the generator and the load.

** Contextless gobbledegook.


Voltage level differences determines reactive power flow.

** Even worse contextless gobbledegook.


The " David " ASD fucked troll generates only meaningless spew.

Must be some kind fuckwit, public service compewter geek with a really tiny
dick.

And no balls at all.

Like Goebells.




.... Phil
 
"TonyS"


** John Tserkezis is a life long, total nut case.

Like the proverbial Zoo Gorilla, he annoys himself.

So, it is a totally superfluous to annoy him with facts or logic.

They are both forever beyond his comprehension.

FFS - wise up.




..... Phil
 
"John Tserkezis" <jt@techniciansyndrome.org.invalid> wrote in message
news:j799kh$oid$1@dont-email.me...
Metro wrote:

Looks like there could be problems ahead. Had to happen I suppose. Not
enough thought went into it........


http://www.theaustralian.com.au/national-affairs/carbon-plan/rooftop-solar-panels-overloading-electricity-grid/story-fn99tjf2-1226165360822

Did you miss the fact that the author of that 'The Australian' article is
a complete knob, and has no idea on how the grid works?
He invents terminology, quotes others out of context, and quotes
installers who have equally no clue on how anything works at all.

The Internet is loaded with lots of information on how the power grid
works in general, and how the different forms of solar controllers work,
AND how they interact with the grid.

I would suggest reading one of those, because *this* article is NOT one
of them.
--
Wth noting that the two towns cited in the article - Exmouth and
Carnarvon - are both relatively small and distant from the main state grids.
AFAIAA both would be reliant on relatively small local generating
facilities, their grid may not be all that stiff.
 
TonyS wrote:

There we go, you just demolished my theory,
as well as the statements of Mr.Hart and the power companies.:)
You're welcome. :)

As I've said, they don't do changes like that, it's a sliding scale,
there is nothing abrubt about it.

So the "tripping out" jargon and in fact most of the article
(http://www.theaustralian.com.au/national-affairs/carbon-plan/rooftop-solar-panels-overloading-electricity-grid/story-fn99tjf2-1226165360822)

is not telling the truth:
You may recall at the start of this thread, I said "is a complete
knob, and has no idea on how the grid works".

I stand by that. It *could* also be correct that he actually DOES
know what he's talking about, but is telling fibs for either profit,
political or other reasons.

And in those cases, he's still a knob. Only politicians have right to
tell outright lies and make themselves look like knobs, because *that's
their job*.

*"Mr Hart, who owns EcoSouth Solar Electricity, said areas with a lot of
solar panels pushed the voltage up to the maximum allowable level,
triggering shutdowns in the individual systems and taking the load off
the grid.
That's false.

He said solar systems "drop out for a few minutes" when voltages get too
high, a phenomenon known as "tripping out".
False again.

"Then they try to come online again and it pushes the voltage up again
and it's very wearing," he said. "That's the problem with having too
much solar in an area where the local authority hasn't got enough wires
or copper in the street to hold the voltage down."*
No clue whatsoever.

The truth would be that with more solar rooftop PV we are not facing
instability but inefficiency (in top of the inefficiency caused by the
power plants running on lower load).
Not sure what you mean here, the only clear inefficiency is that solar
is less cost-effective than solar. Sure there's the minor CO2 issue,
but considering that's where the vast majority of our power comes from,
the tree-huggers had better come up with a cheaper better alternative
rather than say current solar and wind technologies are our saviours -
they are not.

*Mr Hart said the size of conductors and cables in the streets would
have to be upgraded "so it can handle lots of solar, versus times when
there's lots of load and no solar".*
It doesn't work like that. Solar does NOT put anything more into the
wires, than what they can already deal with anyway.
Any power that comes from solar, does not come from the grid, it's not
rocket science.

That's true then, more copper could fix the problem. Obviously no one
wants to pay for that.
It's not true, but yes even if it were, no one would want to pay for it.

Another way would be to monitor the PV installations locally in detail
and not approve new ones unless the lines have been upgraded.
See the last paragraph of the article:
And reduce business? I think not.

*"In Western Australia, Horizon Power has set "hosting capacity limits"
for renewable energy installations."*

I wonder if there could be some other reasons as well....
Agreed, if he IS right on this point (doubt it, but there you go)
there are OTHER reasons for it.
--
Junior! Quit playing with your floppy.
 
"TonyS"


** John Tserkezis is a life long, total nut case.

Like the proverbial Zoo Gorilla, he annoys himself.

So, it is a totally superfluous to annoy him with facts or logic.

They are both forever beyond his comprehension.

FFS - wise up.




..... Phil
 
Bruce Varley wrote:

Wth noting that the two towns cited in the article - Exmouth and
Carnarvon - are both relatively small and distant from the main state grids.
AFAIAA both would be reliant on relatively small local generating
facilities, their grid may not be all that stiff.
It's been a while, but the names ring a bell.

Either limited local generation, or long distance cables causing
voltage lag will do it.
I'm thinking it's more likely to be long distance cables.

Wind is out there to supplement peak power use, and that works well,
if you ignore the constant whining and protesting to get the wind
generators taken out, citing noise and eye-soreness as reasons.

Quite sensibly, they are all ignored.
It's easy to leave the wind generators installed and ignore the
whining and protesting
It's hard to remove the wind generation, and ignore screams of blue
bloody murder when they get to their quiet homes, turn on the lights and
barely get a dim glow.
--
The worst thing about censorship is **************************.
 
On 17/10/2011 12:07 AM, Phil Allison wrote:

"David is a Professional Electrical Engineer with many years experience
in the power industry"

**Care to explain how grid connected inverters are capable of feeding
MORE
than mains Voltage (whether it is a nominal 230VAC or 240VAC) into the
grid?


** No current would flow from the inverter UNLESS it put out more volts
than
were otherwise on the incoming line.


Not true in AC system.


** The topic is domestic premises where load current is normally very close
to being in-phase - and that current exists in the conductors feeding each
premises.
I knew there was no point in explaining this to someone who has no
concept of the difference between phase angle and load angle.

This might be a bit complex for you Phil, but here is a reference for
Wind Generation. Solar is the same:

http://books.google.com.au/books?id=3e-WeiLb848C&pg=PA103&lpg=PA103&dq=power+flow+load+angle&source=bl&ots=dFM2Dji-ks&sig=sbms7yUrdW6W0qWhpkxmx7P4ai0&hl=en&ei=PP2bTsDhIoa1iQff_6msAg&sa=X&oi=book_result&ct=result&resnum=4&ved=0CDUQ6AEwAzgK#v=onepage&q=power%20flow%20load%20angle&f=false
Refer to top of Page 104.


The feed conductors are essentially resistors at 50Hz.
There is a lot more to a power system than "feed conductors", what ever
you mean by that. I take it you are refering to the the consumer mains.

So voltage drop determines the direction of flow.

For reactive power, yes. Not for real power. That depends on the load
angle between the load and the generator

You fucking tenth with moron.

?????????


In an AC power system, real power flow is determined by the load angle
between the generator and the load.


** Contextless gobbledegook.
I knew you wouldn't understand this. It requires some level of
mathematical understanding. AC power systems are a lot more complex than
Ohms law and toasters.

Voltage level differences determines reactive power flow.


** Even worse contextless gobbledegook.

QED

.... David
 
"David is a trolling Fake "


"David is a Professional Electrical Engineer with many years experience in
the power industry"

"David is a LYING trolling Fake "


** No current would flow from the inverter UNLESS it put out more volts
than were otherwise on the incoming line.


Not true in AC system.


** The topic is domestic premises where load current is normally very
close
to being in-phase - and that current exists in the conductors feeding
each
premises.

The feed conductors are essentially resistors at 50Hz.

So voltage drop determines the direction of flow.

You fucking tenth witted moron.


In an AC power system, real power flow is determined by the load angle
between the generator and the load.


** Contextless gobbledegook.


Voltage level differences determines reactive power flow.


** Even worse contextless gobbledegook.

** This anonymous " David " fuckwit has never been right, not even once.

He even got the very simple math relating copper resistance to temp rise
completely fouled up.

Cos he is a mentally defective pile of autistic scum.

Yet another revolting, ASD fucked inbreed.




..... Phil
 
A bit complex is it for you Phil? Couldn't understand the link I sent
you? Good thing toasters are purely resistive loads I guess.

Pity you never understood complex numbers and vectors. You might then
understand about AC power sytems.

David



On 17/10/2011 9:56 PM, Phil Allison wrote:
"David is a trolling Fake"


"David is a Professional Electrical Engineer with many years experience in
the power industry"


"David is a LYING trolling Fake"


** No current would flow from the inverter UNLESS it put out more volts
than were otherwise on the incoming line.


Not true in AC system.


** The topic is domestic premises where load current is normally very
close
to being in-phase - and that current exists in the conductors feeding
each
premises.

The feed conductors are essentially resistors at 50Hz.

So voltage drop determines the direction of flow.

You fucking tenth witted moron.


In an AC power system, real power flow is determined by the load angle
between the generator and the load.


** Contextless gobbledegook.


Voltage level differences determines reactive power flow.


** Even worse contextless gobbledegook.


** This anonymous " David " fuckwit has never been right, not even once.

He even got the very simple math relating copper resistance to temp rise
completely fouled up.

Cos he is a mentally defective pile of autistic scum.

Yet another revolting, ASD fucked inbreed.




.... Phil
 
Phil Allison wrote:

** John Tserkezis is a life long, total nut case.
Like the proverbial Zoo Gorilla, he annoys himself.
So, it is a totally superfluous to annoy him with facts or logic.
They are both forever beyond his comprehension.
FFS - wise up.
Give up Phil. Rod Speed has that market cornered. And he's been
doing it from LONG before *that* condom broke.
--
Everybody wants to go to heaven, but nobody wants to die.
 
"David is a trolling Fake "


"David is a Professional Electrical Engineer with many years experience in
the power industry"

"David is a LYING trolling Fake "


** This anonymous " David " fuckwit has never been right, not even once.

He even got the very simple math relating copper resistance to temp rise
completely fouled up.

Cos he is a mentally defective pile of autistic scum.

Yet another revolting, ASD fucked inbreed.


..... Phil
 
I wish you blokes would not quote Phil's filth and abuse verbatim. Those of
us who killfiled him to avoid it still have to read it! Doesn't take long
to put in asterisks!

"David" <david@usenet.com> wrote in message
news:4e9c26d6$0$10387$c3e8da3$14a0410e@news.astraweb.com...
A bit complex is it for you Phil? Couldn't understand the link I sent you?
Good thing toasters are purely resistive loads I guess.

Pity you never understood complex numbers and vectors. You might then
understand about AC power sytems.

David



On 17/10/2011 9:56 PM, Phil Allison wrote:
"David is a trolling Fake"


"David is a Professional Electrical Engineer with many years experience
in
the power industry"


"David is a LYING trolling Fake"


** No current would flow from the inverter UNLESS it put out more volts
than were otherwise on the incoming line.


Not true in AC system.


** The topic is domestic premises where load current is normally very
close
to being in-phase - and that current exists in the conductors feeding
each
premises.

The feed conductors are essentially resistors at 50Hz.

So voltage drop determines the direction of flow.

You fucking tenth witted moron.


In an AC power system, real power flow is determined by the load angle
between the generator and the load.


** Contextless gobbledegook.


Voltage level differences determines reactive power flow.


** Even worse contextless gobbledegook.


** This anonymous " David " fuckwit has never been right, not even once.

He even got the very simple math relating copper resistance to temp rise
completely fouled up.

Cos he is a mentally defective pile of autistic scum.

Yet another revolting, ASD fucked inbreed.




.... Phil
 
"Dimmer"


** Hey - Dimwit.

Go straight to hell you stinking troll.


... Phil
 
On 17/10/2011 5:58 PM, John Tserkezis wrote:
[snipped the lot to start from scratch but show the article link:

http://www.theaustralian.com.au/national-affairs/carbon-plan/rooftop-solar-panels-overloading-electricity-grid/story-fn99tjf2-1226165360822
]

John, I did a little more research on the subject.
A friend of mine has a solar installer licence and has access to
inverter manuals.
I looked at manuals of the German SMA

(http://www.sma-australia.com.au/en_AU/products/solar-inverters/sunny-boy.html)

and the Chinese Sunteams (www.kinglongpower.com)
which are quite common here in WA.

They do switch off (disconnect from the grid by relay) as soon as the
maximal Voltage has been reached (260 or 265 Volts). No info on
hysteresis and recovery time though.

You can tweak this voltage in the setup (but need a password with the
SMA), and so make sure that at least your system keeps feeding (don't!).

If this design is common practice, which I think is safe to assume, the
scenario described by Mr. Hart sounds plausible to me I am afraid, given
that there is not enough copper and/or a high number of solar feeders.
 

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