The incoming power to our section of road failed at 3am Sunday and it
was 2.35pm (yes, just below the compensation threshold of £150) when
it was restored.

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position
of the bed.


--
AnthonyL

Why do scientists need to BELIEVE in anything?

AnthonyL wrote:

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

How well do you think two houses with solar panels would get on trying
to supply the whole street's cookers/showers/electric cars? Of course
the real reason the inverter shuts itself down is to avoid zapping the
chaps fixing your supply ...

On 26/08/2019 13:24, AnthonyL wrote:
The incoming power to our section of road failed at 3am Sunday and it
was 2.35pm (yes, just below the compensation threshold of £150) when
it was restored.

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position
of the bed.



They could have but they need some extra kit.

One thing they must not do is power the network if its dead, doing so
could get a worker trying to fix it killed.


It wouldn't be difficult to have an inverter and some batteries
connected so the panels would still operate without the mains but you
would also require some sort of switch to ensure you didn't power the
network.

In most cases it isn't worth the cost.

AnthonyL wrote:
It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

They can, if they have batteries and appropriate controls. If they don't
have batteries, they're at risk of a brownout or cut if the sun happens to
go behind a cloud at the wrong moment. That could be unfortunate for
equipment that isn't expecting intermittent power - and isn't uncommon in
our weather.

You can get controls that switch over the house to solar power, while
preventing making the inlet live and frying any technicians working on it,
but presumably your neighbours didn't invest in such things.

Theo

On Mon, 26 Aug 2019 12:24:48 GMT, lid (AnthonyL)
wrote:

The incoming power to our section of road failed at 3am Sunday and it
was 2.35pm (yes, just below the compensation threshold of £150) when
it was restored.

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position
of the bed.

Talking to the owner of a mostly electric narrow boat the other day,
he ditched his solar panels completely (as they failed) as they were
not really able to contribute much to the solution, even on a 'good'
day.

They may have their place, but not even as a UPS on a sunny day
apparently? ;-(

Cheers, T i m

T i m wrote:
Talking to the owner of a mostly electric narrow boat the other day,
he ditched his solar panels completely (as they failed) as they were
not really able to contribute much to the solution, even on a 'good'
day.

They may have their place, but not even as a UPS on a sunny day
apparently? ;-(

Narrow boats are, well, narrow, and moorings are often shaded by trees.
That wouldn't be my first site for a solar installation. Better to have the
panels on land and feed in the power to the boat via a wire with a mains
plug on the end.

THeo

On 26 Aug 2019 14:22:34 +0100 (BST), Theo
wrote:

T i m wrote:
Talking to the owner of a mostly electric narrow boat the other day,
he ditched his solar panels completely (as they failed) as they were
not really able to contribute much to the solution, even on a 'good'
day.

They may have their place, but not even as a UPS on a sunny day
apparently? ;-(

Narrow boats are, well, narrow,

Yeah, but they are about as wide as a reasonable Solar Panel and often
60-70' long. ;-)

and moorings are often shaded by trees.

That is true.

That wouldn't be my first site for a solar installation.

No, but many do have quite a few panels so I'm guessing they mush have
some use, if only / mostly in the summer and for recovering *some*
charge in the Aux / Main batteries?

Better to have the
panels on land and feed in the power to the boat via a wire with a mains
plug on the end.

Again, you are right of course [1] but that sorta defeats the whole
'mobile / off grid home' thing. ;-)

In this case the boat is equipped with a 600cc twin cylinder diesel
engine that is run high up in it's efficiency curve when needed to
(only) charge the batteries.

As a spinoff of that the engine also provides underfloor heating via
it's cooling circuits.

The interesting bit is that he was saying that the LA batteries really
needed regular (fortnightly) 'balancing' and if running off grid, that
mean running the engine / generator at less than a full load for
several (~5-6) hours. If a mains power socket was available that is
much more efficient of course.

As an alternative to using the generator for the balancing /
equalisation / de-stratification stage, he was considering using some
form of Lithium battery or even SuperCapacitor, as they could use the
spare power after the end of the main battery bulk charge phase and
neither would need much balancing?

I've not read / absorbed all the tech details on his handout yet but
he was also saying the boat was too heavy and he will have to remove
some ballast. I was surprised to learn that the batteries weren't part
of that ballast (in the bilges etc) but were in the main accommodation
area as such?

So his was a 'diesel electric' (with batteries) in a similar way a
diesel electric train or ship might be, whereas some other hybrid
boats could drive the prop with electric motors or the IC engine
directly. Apparently that causes a big compromise because of the revs
/ torque available and he the size of prop required (bigger for
electric). But why couldn't they drive the big electric prop from the
IC engine via a reduction gearbox of some sort? Reduced efficient
(losses in the gearbox) possibly?

Cheers, T i m

[1] Someone was asking me about the idea of a solar powered, battery
stored, portable waterpump for allotment use. The water is delivered
to IBC tanks via some plumbing (and water butts from the rain etc) but
needs to be delivered to the plants manually. I suggested that maybe a
leisure battery and suitable low power pump (possibly submersible)
could do the job but like you, suggested the panels might be on top of
a 'docking shed' or some such?

On Monday, 26 August 2019 14:51:28 UTC+1, T i m wrote:
I was surprised to learn that the batteries weren't part
of that ballast (in the bilges etc) but were in the main accommodation
area as such?

Bilges tend to be wet and mucky places, not the ideal location for batteries.

Owain

Graham. wrote:

if you wanted solar energy you could directly use
yourself, maybe it was mid-sold?

The ambulance chasing lawyers do need a new target after next Thursday's
PPI deadline ...

On Monday, 26 August 2019 13:24:50 UTC+1, AnthonyL wrote:
The incoming power to our section of road failed at 3am Sunday and it
was 2.35pm (yes, just below the compensation threshold of £150) when
it was restored.

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position
of the bed.



Grid linked solar panels are designed to be "anti islanding".
It's a safety thing and it would be impossible for them to meet the load alone.

https://en.wikipedia.org/wiki/Islanding


You can get a "stand alone" system for more money which has batteries included.

https://en.wikipedia.org/wiki/Stand-alone_power_system

On 26/08/2019 13:24, AnthonyL wrote:
The incoming power to our section of road failed at 3am Sunday and it
was 2.35pm (yes, just below the compensation threshold of £150) when
it was restored.

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

They have to drop out or be isolated completely from the mains grid and
then be provided a reference 50Hz pilot. It is possible but not common
as it is more expense and complexity for a rare situation.

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position
of the bed.

Someone in that position should have an automatic fallback so that when
external mains fails the system can be switched to internal power and a
generator set starts up (with manual intervention or more expensively
automatically start up after mains power fail). The guy who lived
opposite had such a system to support his 95 year old father in law.

--
Regards,
Martin Brown

On 26/08/2019 14:07, Theo wrote:
AnthonyL wrote:
It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

They can, if they have batteries and appropriate controls. If they don't
have batteries, they're at risk of a brownout or cut if the sun happens to
go behind a cloud at the wrong moment. That could be unfortunate for
equipment that isn't expecting intermittent power - and isn't uncommon in
our weather.

You can get controls that switch over the house to solar power, while
preventing making the inlet live and frying any technicians working on it,
but presumably your neighbours didn't invest in such things.

Theo


No standard PV insulation has off-grid enabled. They need to
rely on power from the network to generate the correct waveform
for starters (didn't we have this discussion with the recent
failures at a wind farm?), and also there is the safety aspect
so you don't electrocute someone working on the line.

This also begs the question, if the frequency dropped below
48.whatever, shouldn't thousands of domestic PV systems say,
ooops, don't like this, and shut down too?.

On 26/08/2019 15:29, Andy Burns wrote:
Graham. wrote:

if you wanted solar energy you could directly use
Â* yourself, maybe it was mid-sold?

The ambulance chasing lawyers do need a new target after next Thursday's
PPI deadline ...

I'm waiting for all those 'aggrieved' state pensioners who were
contracted out for much or even part of their lives, to demand
COMPO for their 'loss' of the full 'new' state pension.

How about car owners who have never made a claim ?. They'll
be wanting their premiums back.

On 26/08/2019 15:51, Martin Brown wrote:
On 26/08/2019 13:24, AnthonyL wrote:
The incoming power to our section of road failed at 3am Sunday and it
was 2.35pm (yes, just below the compensation threshold of £150) when
it was restored.

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation?Â* No way.Â* The bloody
things need electrical power to operate.

They have to drop out or be isolated completely from the mains grid and
then be provided a reference 50Hz pilot. It is possible but not common
as it is more expense and complexity for a rare situation.

Not even a cup of tea.Â* Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position
of the bed.

Someone in that position should have an automatic fallback so that when
external mains fails the system can be switched to internal power and a
generator set starts up (with manual intervention or more expensively
automatically start up after mains power fail). The guy who lived
opposite had such a system to support his 95 year old father in law.


Friends up the road have these. There are two big rotary switches
(those things sitting in a wall box, and are about 4 inches across).

One (I think) cuts off the DC power to the panel, the other isolates
the output from the inverter from the mains.

On 26/08/2019 19:55, Andrew wrote:
This also begs the question, if the frequency dropped below
48.whatever, shouldn't thousands of domestic PV systems say,
ooops, don't like this, and shut down too?.
They did. 1/2GW dropped off the grid.


--
"A point of view can be a dangerous luxury when substituted for insight
and understanding".

Marshall McLuhan

On 26/08/2019 15:33, Jethro_uk wrote:
On Mon, 26 Aug 2019 12:24:48 +0000, AnthonyL wrote:

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position of
the bed.

Well it *used* to be such systems were inherently battery powered, and
could survive a loss of mains power.

NHS outreach beds don't have a battery. All stairlifts do have a battery.

Bill

On 26/08/2019 20:45, Bill Wright wrote:
On 26/08/2019 15:33, Jethro_uk wrote:
On Mon, 26 Aug 2019 12:24:48 +0000, AnthonyL wrote:

Not even a cup of tea.Â* Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position of
the bed.

Well it *used* to be such systems were inherently battery powered, and
could survive a loss of mains power.

NHS outreach beds don't have a battery. All stairlifts do have a battery.

Bill

The Himolla Zero Stress reclining chairs either run off a big
brick transformer or a battery pack, so its not difficult to do.

On Mon, 26 Aug 2019 20:45:08 +0100, Bill Wright
wrote:

On 26/08/2019 15:33, Jethro_uk wrote:
On Mon, 26 Aug 2019 12:24:48 +0000, AnthonyL wrote:

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position of
the bed.

Well it *used* to be such systems were inherently battery powered, and
could survive a loss of mains power.

NHS outreach beds don't have a battery.

I'm not sure what an 'outreach bed' is but I'm sure the bed they gave
(loaned) my step-daughter earlier this year before she went into the
hospice was battery equipped?

It was one of those that constantly inflated and deflated the mattress
slightly to prevent bed sores and I know it beeped if you unplugged
the main box bit (because we did whilst sorting it all out)?

Cheers, T i m

On 26/08/2019 20:45, Bill Wright wrote:
On 26/08/2019 15:33, Jethro_uk wrote:
On Mon, 26 Aug 2019 12:24:48 +0000, AnthonyL wrote:

Not even a cup of tea.Â* Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position of
the bed.

Well it *used* to be such systems were inherently battery powered, and
could survive a loss of mains power.

NHS outreach beds don't have a battery. All stairlifts do have a battery.

Bill

What's an outreach bed?
The ones in the wards have batteries.

On Mon, 26 Aug 2019 06:56:22 -0700 (PDT),
wrote:

On Monday, 26 August 2019 14:51:28 UTC+1, T i m wrote:
I was surprised to learn that the batteries weren't part
of that ballast (in the bilges etc) but were in the main accommodation
area as such?

Bilges tend to be wet and mucky places, not the ideal location for batteries.

True, but I was thinking there could be something in between?

The idea was that you have the basic ballast in the real bilges
(presumed fairly flat bottomed on yer average narrow boat) with an
allowance for the batteries, potentially an inner tray, sealed from
the bilge but still under the floor and vented directly to the outside
(you don't typically need much freeboard on the rivers and canals).

According to the handout, 'Ampere' carries a working capacity of 48kW
at 48V using 24 x 2V 'traction cells' that are 600mm deep (so may well
go quite a way into the bilges as it is)?

Luckily, I don't suppose the 1.6 tonnes of batteries would even be
noticed (weight wise anyway) in a 60+' narrow boat. ;-)

Cheers, T i m

"dennis@home" wrote in message
...
On 26/08/2019 13:24, AnthonyL wrote:
The incoming power to our section of road failed at 3am Sunday and it
was 2.35pm (yes, just below the compensation threshold of £150) when
it was restored.

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position
of the bed.



They could have but they need some extra kit.

One thing they must not do is power the network if its dead, doing so
could get a worker trying to fix it killed.

In theory. In practice they mostly work live even when
there are no solar panels anywhere.

It wouldn't be difficult to have an inverter and some batteries connected
so the panels would still operate without the mains but you would also
require some sort of switch to ensure you didn't power the network.

In most cases it isn't worth the cost.

On Tue, 27 Aug 2019 08:25:32 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


In theory. In practice

The senile Ozzie cretin knows it ALL better, AGAIN and AGAIN and AGAIN...

--
Keema Nam addressing nym-shifting senile Rodent:
"You are now exposed as a liar, as well as an ignorant troll."
"MID: .com"

Yes I've always thought this was bleedin stupid. It would be a trivial thing
to have a set of deep discharge batteries and the inverter under manual
control for just such an occasion. It is done in some less developed
countries, no doubt a bit heath Robinson, but still. The current kit is
really all about to same money and not add functionality.
All I will say is that I have a friend who has hot water panels on the roof
and although you cannot power the stereo or tv from it you can get hot
water. The pump uses very little and can run on a small inverter you can
pick up cheaply.
Its a strange world we live in.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"AnthonyL" wrote in message
...
The incoming power to our section of road failed at 3am Sunday and it
was 2.35pm (yes, just below the compensation threshold of £150) when
it was restored.

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position
of the bed.


--
AnthonyL

Why do scientists need to BELIEVE in anything?

No its trivial to fix it so that this does not happen in the event of a
complete power outage.
They either are more stupid than they seem or its just cost cutting.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Andy Burns" wrote in message
...
AnthonyL wrote:

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

How well do you think two houses with solar panels would get on trying to
supply the whole street's cookers/showers/electric cars? Of course the
real reason the inverter shuts itself down is to avoid zapping the chaps
fixing your supply ...

lid (AnthonyL) Wrote in message:
The incoming power to our section of road failed at 3am Sunday and it
was 2.35pm (yes, just below the compensation threshold of £150) when
it was restored.

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position
of the bed.


--
AnthonyL

Why do scientists need to BELIEVE in anything?


I admire your altruism in choosing a system that benefits the rest
of us, but if you wanted solar energy you could directly use
yourself, maybe it was mid-sold? (!)
--

Graham.
%Profound_observation%


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On Mon, 26 Aug 2019 20:29:00 +0100, The Natural Philosopher wrote:

This also begs the question, if the frequency dropped below
48.whatever, shouldn't thousands of domestic PV systems say,
ooops, don't like this, and shut down too?.

They did. 1/2GW dropped off the grid.

Isn't that an guesstimated 1/2 GW? As it's embedded in the
distribution and not monitored/metered, all they see is a (slight)
reduction in demand from their forecast. Probably well within the
error bars of that forecast.

I don't think the loss of this embedded capacity is included in the
offical figures for how much power the grid lost on that Friday.

--
Cheers
Dave.

On Tuesday, 27 August 2019 08:18:27 UTC+1, Brian Gaff wrote:
No its trivial to fix it so that this does not happen in the event of a
complete power outage.
They either are more stupid than they seem or its just cost cutting.
Brian


It's not in the slightest trivial.

On Tuesday, 27 August 2019 08:17:09 UTC+1, Brian Gaff wrote:
Yes I've always thought this was bleedin stupid. It would be a trivial thing
to have a set of deep discharge batteries and the inverter under manual
control for just such an occasion. It is done in some less developed
countries, no doubt a bit heath Robinson, but still. The current kit is
really all about to same money and not add functionality.
All I will say is that I have a friend who has hot water panels on the roof
and although you cannot power the stereo or tv from it you can get hot
water. The pump uses very little and can run on a small inverter you can
pick up cheaply.
Its a strange world we live in.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"AnthonyL" wrote in message
...
The incoming power to our section of road failed at 3am Sunday and it
was 2.35pm (yes, just below the compensation threshold of £150) when
it was restored.

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position
of the bed.


The solar panels are wired in series for about 500Vdc in full sunshine.
How are you going to cheaply fix this?

On 27/08/2019 11:17, Dave Liquorice wrote:
On Mon, 26 Aug 2019 20:29:00 +0100, The Natural Philosopher wrote:

This also begs the question, if the frequency dropped below
48.whatever, shouldn't thousands of domestic PV systems say,
ooops, don't like this, and shut down too?.

They did. 1/2GW dropped off the grid.

Isn't that an guesstimated 1/2 GW? As it's embedded in the
distribution and not monitored/metered, all they see is a (slight)
reduction in demand from their forecast. Probably well within the
error bars of that forecast.

I don't think the loss of this embedded capacity is included in the
offical figures for how much power the grid lost on that Friday.

Presumably the loss of embedded capacity would be shown by a matching
increase in demand that we can see in some cases... (although not if the
whole area has already been dropped)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Mon, 26 Aug 2019 15:13:30 +0100 (GMT+01:00), "Graham."
wrote:

(AnthonyL) Wrote in message:
The incoming power to our section of road failed at 3am Sunday and it
was 2.35pm (yes, just below the compensation threshold of £150) when
it was restored.

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position
of the bed.


--
AnthonyL

Why do scientists need to BELIEVE in anything?


I admire your altruism in choosing a system that benefits the rest
of us, but if you wanted solar energy you could directly use
yourself, maybe it was mid-sold? (!)

Comprehension failure due to too much sun perhaps?

--
AnthonyL

Why do scientists need to BELIEVE in anything?

On Mon, 26 Aug 2019 15:51:31 +0100, Martin Brown
wrote:

On 26/08/2019 13:24, AnthonyL wrote:
The incoming power to our section of road failed at 3am Sunday and it
was 2.35pm (yes, just below the compensation threshold of £150) when
it was restored.

It was of course a nice sunny day - ideal for solar generation, and
both my next door neighbour and the house opposite have got panels.
Could they take advantage of the situation? No way. The bloody
things need electrical power to operate.

They have to drop out or be isolated completely from the mains grid and
then be provided a reference 50Hz pilot. It is possible but not common
as it is more expense and complexity for a rare situation.


I'm not asking why it is so, I'm stating that there is no/little
resilience in commonly sold systems and I doubt that my neighbours
would have had that explained to them.

Not even a cup of tea. Or more seriously the woman at the house
opposite is bed bound and needs a bit of power to change the position
of the bed.

Someone in that position should have an automatic fallback so that when
external mains fails the system can be switched to internal power and a
generator set starts up (with manual intervention or more expensively
automatically start up after mains power fail). The guy who lived
opposite had such a system to support his 95 year old father in law.


Most people would not have expected to design a system for an 11.5hr
power outage within a reasonably large city boundary.

An hour or two would not have been a problem.

Anyhow Western Power quite quickly hooked up an external generator
which of course involved removing the household from the grid.

--
AnthonyL

Why do scientists need to BELIEVE in anything?

On Tue, 27 Aug 2019 03:31:46 -0700 (PDT), harry
wrote:


The solar panels are wired in series for about 500Vdc in full sunshine.
How are you going to cheaply fix this?

Thankfully someone realises there is a limit to the subsidies we have
to pay.

--
AnthonyL

Why do scientists need to BELIEVE in anything?

On 27/08/2019 11:17, Dave Liquorice wrote:
On Mon, 26 Aug 2019 20:29:00 +0100, The Natural Philosopher wrote:

This also begs the question, if the frequency dropped below
48.whatever, shouldn't thousands of domestic PV systems say,
ooops, don't like this, and shut down too?.

They did. 1/2GW dropped off the grid.

Isn't that an guesstimated 1/2 GW? As it's embedded in the
distribution and not monitored/metered, all they see is a (slight)
reduction in demand from their forecast. Probably well within the
error bars of that forecast.

No. they see an immediate and sudden drop as the frequency goes down.
That is they will see a step change in DEMAND, upwards...


It's the size of the total step before load shedding

It's in either the OFCOM report or Kathryn Porter's - cant remember
which or both..


I don't think the loss of this embedded capacity is included in the
offical figures for how much power the grid lost on that Friday.

Well it is included in it actually

http://watt-logic.com/2019/08/21/blackout-report/

"*According to the report*...

.....Three things then occurred almost simultaneously:

1. The Hornsea off-shore windfarm suddenly de-loaded its supply to
the grid from 799 MW to 62 MW (only units 2 and 3 were affected €“ unit 1
continued to operate at 50 MW throughout the event);
2. The steam turbine at the Little Barford CCGT which is connected
to Eaton Socon 400kV substation at one end of the affected line,
tripped; and
3. The sudden shift in the angle of the voltage caused some
distributed generators, mainly be solar and some small gas and diesel
plant, to detect €œloss of mains€� and automatically disconnect from the
system.

The reduction in generation from these events was:

737 MW €“ Hornsea
244 MW €“ Little Barford
c 500 MW €“ embedded generation

The cumulative amount of lost generation was 1,481 MW, 48% above the
1,000 MW single loss protection level at which the system was running at
the time. (The system is designed so that it can continue to operate if
the single largest generation unit trips at any time, which might be a
large nuclear plant, or an interconnector.)"

So yes it is an estimate, but in this case a pretty close one.





--
The theory of Communism may be summed up in one sentence: Abolish all
private property.

Karl Marx

On Tue, 27 Aug 2019 13:17:31 +0100, The Natural Philosopher wrote:

Isn't that an guesstimated 1/2 GW? As it's embedded in the
distribution and not monitored/metered, all they see is a (slight)
reduction in demand from their forecast. Probably well within the
error bars of that forecast.

No. they see an immediate and sudden drop as the frequency goes down.
That is they will see a step change in DEMAND, upwards...

I was thinking under normal conditions. With the embedded stuff only
showing up as a reduction in demand for a given area from the grids
predictions, assuming said prediction doesn't make allowance for the
embedded stuff. Which I expect it does, otherwise the margin will end
up too big.

The reduction in generation from these events was:

737 MW Hornsea
244 MW Little Barford
c 500 MW embedded generation

The cumulative amount of lost generation was 1,481 MW,

Ah that Lttle Barford figure has changed from what I remember. Must
get aroound to reading the proper reports sometime...

--
Cheers
Dave.

On 27/08/2019 19:28, Dave Liquorice wrote:
On Tue, 27 Aug 2019 13:17:31 +0100, The Natural Philosopher wrote:

Isn't that an guesstimated 1/2 GW? As it's embedded in the
distribution and not monitored/metered, all they see is a (slight)
reduction in demand from their forecast. Probably well within the
error bars of that forecast.

No. they see an immediate and sudden drop as the frequency goes down.
That is they will see a step change in DEMAND, upwards...

I was thinking under normal conditions. With the embedded stuff only
showing up as a reduction in demand for a given area from the grids
predictions, assuming said prediction doesn't make allowance for the
embedded stuff. Which I expect it does, otherwise the margin will end
up too big.

The reduction in generation from these events was:

737 MW â Hornsea
244 MW â Little Barford
c 500 MW â embedded generation

The cumulative amount of lost generation was 1,481 MW,

Ah that Lttle Barford figure has changed from what I remember. Must
get aroound to reading the proper reports sometime...

I think that sbesequently Barford dropped its OCGT half - IIRC it is
480MW OCGT and 244MW steam...

A shade under 2GW in all.



--
€œIt is hard to imagine a more stupid decision or more dangerous way of
making decisions than by putting those decisions in the hands of people
who pay no price for being wrong.€�

Thomas Sowell

On Mon, 26 Aug 2019 23:23:03 +0100, T i m wrote:

According to the handout, 'Ampere' carries a working capacity of 48kW
...

That's a lot of power for a narrow boat, 1 hp (approx 750 W) is all
they needed orginally for propulsion. B-) Modern gadgets like
electric lights, fridge, ain't going to add much more than 1 kW.

... at 48V using 24 x 2V 'traction cells' that are 600mm deep (so may
well go quite a way into the bilges as it is)?

I suspect the common confusion between power (kW) and energy (kWHr).
B-)

Luckily, I don't suppose the 1.6 tonnes of batteries would even be
noticed (weight wise anyway) in a 60+' narrow boat. ;-)

IIRC a 70' narrow boat has maximum payload of 60+ tons. So 1.6 is
bugger all but will affect the trim. One wouldn't shove them all down
one side or all at one end...

--
Cheers
Dave.

On 27/08/2019 19:28, Dave Liquorice wrote:
On Tue, 27 Aug 2019 13:17:31 +0100, The Natural Philosopher wrote:

Isn't that an guesstimated 1/2 GW? As it's embedded in the
distribution and not monitored/metered, all they see is a (slight)
reduction in demand from their forecast. Probably well within the
error bars of that forecast.

No. they see an immediate and sudden drop as the frequency goes down.
That is they will see a step change in DEMAND, upwards...

I was thinking under normal conditions. With the embedded stuff only
showing up as a reduction in demand for a given area from the grids
predictions, assuming said prediction doesn't make allowance for the
embedded stuff. Which I expect it does, otherwise the margin will end
up too big.

The reduction in generation from these events was:

737 MW â Hornsea
244 MW â Little Barford
c 500 MW â embedded generation

The cumulative amount of lost generation was 1,481 MW,

Ah that Lttle Barford figure has changed from what I remember. Must
get aroound to reading the proper reports sometime...

He is right they were the instantaneous drop-offs that occurred within
the first seconds of the strike. In the case of Hornsea about 340ms from
the transmission line protection circuit triggering.

The rest of Little Barford soldiered on for about a minute and then
another unit tripped out followed by the third one 30s later (by which
time load shedding had begun and the frequency was already rising).

The annotated frequency vs time diagram in the report is most
enlightening. You want page 13 in this:

https://www.ofgem.gov.uk/system/file...ry_-_final.pdf

--
Regards,
Martin Brown

I don't think so.

You could have a complete parallel DC system in the house
powering lights ?, special DC immersion heater and then an
inverter for local 230VAC stuff but not mains connected.

That or a meaty UPS setup of some sort.

This defeats the main purpose of domestic PV panels though which is
to milk the subsidies and you need to be on the grid to do that.



On 27/08/2019 08:18, Brian Gaff wrote:
No its trivial to fix it so that this does not happen in the event of a
complete power outage.
They either are more stupid than they seem or its just cost cutting.
Brian

On 26/08/2019 14:51, T i m wrote:

[1] Someone was asking me about the idea of a solar powered, battery
stored, portable waterpump for allotment use. The water is delivered
to IBC tanks via some plumbing (and water butts from the rain etc) but
needs to be delivered to the plants manually. I suggested that maybe a
leisure battery and suitable low power pump (possibly submersible)
could do the job but like you, suggested the panels might be on top of
a 'docking shed' or some such?

I have done this particular thing using a submersible solar powered pump
that was intended to run a fountain with about 3m head of water
pressure. It was programmed to run two slots of half an hour a day
morning and evening to run hoselock drop lines in my greenhouse.

The original came from bankrupt stock as the solar powered fountain was
distinctly unimpressive. Nothing wrong with the pump though when
connected to a decent supply it packed quite a punch.

Only complication was it needed a stocking fine filter on the inlet
otherwise mosquito larvae would jam the jets on the drip lines. Solar
power wasn't a design win for it though - it was much easier to lug a
charged 12Ah SLA battery up to the greenhouse and swap it as needed.

--
Regards,
Martin Brown