This is purely curiosity.

Can anyone explain in few words how this stuff works? I'v looked on the
net and only found long, boring academic papers.

I have 2 houses with PV.

This one is off grid so not really an issue, but the other has just 12
panels and no battery and the inverter has a certificate saying it is
guaranteed to shut down in case of grid interruption. It does seem to do
this.

I was wondering

a: how does it detect a dead grid?

b: how does it sync with the grid when they are working together?

One more thing: the RCD (auto-rearming) often trips for no apparent
reason and I was wondering if it could be related to phase sync. Having
said that, it usually happens in bad weather, so prolly not.

Here there is no distributed earth. I wonder if maybe this house is
generating harmonics in the whole street or summat. The N is earthed in
this house.

--
Paul.

https://paulc.es/elpatio

On Sun, 23 Oct 2022 09:41:25 +0000, Paul Carmichael wrote:

> I have 2 houses with PV.
>
> This one is off grid so not really an issue, but the other has just 12
> panels and no battery and the inverter has a certificate saying it is
> guaranteed to shut down in case of grid interruption. It does seem to do
> this.
>
> I was wondering
>
> a: how does it detect a dead grid?

There will be either a contactor, or, more likely, a solid state relay
type device which is powered by the grid, and will drop out if the grid
power is interrupted. It is also likely to have an auto recloser when the
Grid comes back online.

> b: how does it sync with the grid when they are working together?

Sensors in the Inverter will synchronise the waveform of the outgoing
power.
> One more thing: the RCD (auto-rearming) often trips for no apparent
> reason and I was wondering if it could be related to phase sync. Having
> said that, it usually happens in bad weather, so prolly not.

Shouldnt think so if it is just a RCD, they are there for an imbalance of
live to neutral. Water ingress is the biggest cause of RCD trips IME.

> Here there is no distributed earth. I wonder if maybe this house is
> generating harmonics in the whole street or summat. The N is earthed in
> this house.

Unlikely. Most UK houses are TN-C-S earthing system, where the neutral
and earth are combined at the incoming connection to the house, so it isnt
unusual.

El Sun, 23 Oct 2022 10:17:31 +0000, Alan escribió:

>> Here there is no distributed earth. I wonder if maybe this house is
>> generating harmonics in the whole street or summat. The N is earthed in
>> this house.
>
> Unlikely. Most UK houses are TN-C-S earthing system, where the neutral
> and earth are combined at the incoming connection to the house, so it
> isnt unusual.

Our earth is a massive metal cage type thing under the house. When we
first came here, houses just simply didn't have earth connections. We
used to get shocks from white goods because of inductance in the (not
earthed) earth core.

--
Paul.

https://paulc.es/elpatio

Paul Carmichael <wibbleypants@gmail.com> wrote in news:pan$9c7$eaf901b0
$3a0de3ee$a366c3ce@gmail.com:

> El Sun, 23 Oct 2022 10:17:31 +0000, Alan escribió:
>
>>> Here there is no distributed earth. I wonder if maybe this house is
>>> generating harmonics in the whole street or summat. The N is earthed in
>>> this house.
>>
>> Unlikely. Most UK houses are TN-C-S earthing system, where the neutral
>> and earth are combined at the incoming connection to the house, so it
>> isnt unusual.
>
>
> Our earth is a massive metal cage type thing under the house. When we
> first came here, houses just simply didn't have earth connections. We
> used to get shocks from white goods because of inductance in the (not
> earthed) earth core.
>
>

I guess the rod type, domestic earths we use in the UK would not be very
reliable in your arid climate unless you pissed on it daily.

El Sun, 23 Oct 2022 10:47:39 +0000, wessie escribió:

> Paul Carmichael <wibbleypants@gmail.com> wrote in news:pan$9c7$eaf901b0
> $3a0de3ee$a366c3ce@gmail.com:
>
>> El Sun, 23 Oct 2022 10:17:31 +0000, Alan escribió:
>>
>>>> Here there is no distributed earth. I wonder if maybe this house is
>>>> generating harmonics in the whole street or summat. The N is earthed
>>>> in this house.
>>>
>>> Unlikely. Most UK houses are TN-C-S earthing system, where the neutral
>>> and earth are combined at the incoming connection to the house, so it
>>> isnt unusual.
>>
>>
>> Our earth is a massive metal cage type thing under the house. When we
>> first came here, houses just simply didn't have earth connections. We
>> used to get shocks from white goods because of inductance in the (not
>> earthed) earth core.
>>
>>
>>
> I guess the rod type, domestic earths we use in the UK would not be very
> reliable in your arid climate unless you pissed on it daily.

They are legal (1.5m min), but we had this house extended out the back
and had a total re-wire, which requires a tad more committment. Have to
do it to get the new paperwork "Boletín". Can't get a supply without it.

--
Paul.

https://paulc.es/elpatio

On 23/10/2022 10:41, Paul Carmichael wrote:
> This is purely curiosity.
>
> Can anyone explain in few words how this stuff works? I'v looked on the
> net and only found long, boring academic papers.
>
> I have 2 houses with PV.
>
> This one is off grid so not really an issue, but the other has just 12

"just" 12!
6 is the average around here, apparently.
>

--
Bruce Porter
"The internet is a huge and diverse community but mainly friendly"
http://ytc1.blogspot.co.uk/
There *is* an alternative! http://www.openoffice.org/

El Sun, 23 Oct 2022 14:23:50 +0100, YTC#1 escribió:

> On 23/10/2022 10:41, Paul Carmichael wrote:
>> This is purely curiosity.
>>
>> Can anyone explain in few words how this stuff works? I'v looked on the
>> net and only found long, boring academic papers.
>>
>> I have 2 houses with PV.
>>
>> This one is off grid so not really an issue, but the other has just 12
>
> "just" 12!
> 6 is the average around here, apparently.
>>

Mine are older. 250/280w.

12 panels power the pool pump/heater around there.

This house has 30 panels and rather a lot of lead and sulphuric acid in
the loft.

--
Paul.

https://paulc.es/elpatio

On 23/10/2022 14:23, YTC#1 wrote:
>
> On 23/10/2022 10:41, Paul Carmichael wrote:
>> This is purely curiosity.
>>
>> Can anyone explain in few words how this stuff works? I'v looked on the
>> net and only found long, boring academic papers.
>>
>> I have 2 houses with PV.
>>
>> This one is off grid so not really an issue, but the other has just 12
>
> "just" 12!
> 6 is the average around here, apparently.

But we get so much more sun.

On 23/10/2022 10:41, Paul Carmichael wrote:
> a: how does it detect a dead grid?

bearing in mind that Andy Burns corrected me when I said the inverter
tries to lead the phase of the grid and he said the current was only
dictated by the voltage.

It is much the same way a rotating generator connected to the grid works

the analogy is like towing a massive boat along a canal with a two
horses, one an old carthorse and the other a yearling eager to race. The
boat is the load on the grid and the old plodding horse it the grid
generation fixed at 50Hz. Try as he might the young horse cannot pull
the load any faster.

If the grid horse stops plodding on at his fixed 3mph (50Hz) the
connection to the young horse snaps and the young horse races away but
the horseman has the reins, sees the horse trying to run and pulls him
to a stop. If the tow rope was too big to break the load would all come
onto the young horse and he would be dragged to a stop.

In the same way a rotating generator becomes synchronised to the grid
(in the old days by having an incandescent bulb connected across a phase
on the grid and a phase on the generator when the bulb stops glowing
they are in sync and the connection can be made) once it is connected
the throttle is opened and it tries to rev higher, but it cannot as the
grid is too large, if the grid disappears the generator suddenly runs
faster, this is detected and it is shut down.
>
> b: how does it sync with the grid when they are working together?

The inverters have very clever electronics which synchronise them then
they try and run faster as above, cannot, so their push is seen as a
higher voltage which drive the current into the grid.

On 23/10/2022 14:38, Paul Carmichael wrote:
> El Sun, 23 Oct 2022 14:23:50 +0100, YTC#1 escribió:
>
>> On 23/10/2022 10:41, Paul Carmichael wrote:
>>> This is purely curiosity.
>>>
>>> Can anyone explain in few words how this stuff works? I'v looked on the
>>> net and only found long, boring academic papers.
>>>
>>> I have 2 houses with PV.
>>>
>>> This one is off grid so not really an issue, but the other has just 12
>>
>> "just" 12!
>> 6 is the average around here, apparently.
>>>
>
>
> Mine are older. 250/280w.
>
> 12 panels power the pool pump/heater around there.

Pool!

>
> This house has 30 panels and rather a lot of lead and sulphuric acid in
> the loft.
>
>

Acid !
:-)

--
Bruce Porter
"The internet is a huge and diverse community but mainly friendly"
http://ytc1.blogspot.co.uk/
There *is* an alternative! http://www.openoffice.org/

On 23/10/2022 17:41 Paul Carmichael penned these words:
> the RCD (auto-rearming) often trips for no apparent
> reason and I was wondering if it could be related to phase sync

More likely IWHT to be something that powers on and is one the edge as it were.
Does it still happen with everything in the gaff disconnected?
--
Ian

"Man will never be free until the last king is strangled with the entrails of
the last priest"

On 23/10/2022 20:13, YTC#1 wrote:
>
>
> On 23/10/2022 14:38, Paul Carmichael wrote:
>> El Sun, 23 Oct 2022 14:23:50 +0100, YTC#1 escribió:
>>
>>> On 23/10/2022 10:41, Paul Carmichael wrote:
>>>> This is purely curiosity.
>>>>
>>>> Can anyone explain in few words how this stuff works? I'v looked on the
>>>> net and only found long, boring academic papers.
>>>>
>>>> I have 2 houses with PV.
>>>>
>>>> This one is off grid so not really an issue, but the other has just 12
>>>
>>> "just" 12!
>>> 6 is the average around here, apparently.
>>>>
>>
>>
>> Mine are older. 250/280w.
>>
>> 12 panels power the pool pump/heater around there.
>
> Pool!

I prefer billiards or snooker.

>> This house has 30 panels and rather a lot of lead and sulphuric acid in
>> the loft.
>>
>>
>
> Acid !
> :-)

I don't have a loft, just an attic room. While this might do, in
practice, it rather reduces the room's utility. *BUT* I have a brick and
clay lump shed which is much closer to the meters and mains ingress.

In my ill-spent past I'd have been tempted to convert the lead into
ball: for the m/l rifles and pistols...

--
Rusty Hinge
To err is human. To really foul things up requires a computer and the BOFH.

El Mon, 24 Oct 2022 07:34:30 +0800, Boots escribió:

> On 23/10/2022 17:41 Paul Carmichael penned these words:
>> the RCD (auto-rearming) often trips for no apparent reason and I was
>> wondering if it could be related to phase sync
>
> More likely IWHT to be something that powers on and is one the edge as
> it were.
> Does it still happen with everything in the gaff disconnected?

Dunno. It seems to happen randomly. I think it may be related to rain,
but it hardly ever rains here, so difficult to reproduce.

--
Paul.

https://paulc.es/elpatio

ajh wrote:

> once it is connected the throttle is opened and it tries to rev higher, but it
> cannot as the grid is too large, if the grid disappears the generator suddenly
> runs faster, this is detected and it is shut down.

yes, that is exactly how they detect loss of grid.

On 23 Oct 2022 09:41:25 GMT, Paul Carmichael <wibbleypants@gmail.com>
wrote:

>One more thing: the RCD (auto-rearming) often trips for no apparent
>reason and I was wondering if it could be related to phase sync. Having
>said that, it usually happens in bad weather, so prolly not.

No. Conventional RCDs work by measuring the current difference between
L & N. I There are such things as borrowed neutrals, which might
explain it, but I'll leave figuring if and how to someone who know
more than me.

>Here there is no distributed earth. I wonder if maybe this house is
>generating harmonics in the whole street or summat. The N is earthed in
>this house.

Harmonics implies more than one frequency: if that were the case then
you think your inverter might be free-running slightly off mains
frequency? But then you say the off-grid one isn't an issue. If the
on-grid one were running off frequency then there would be times when
it would be in antiphase with the mains, which would cause
considerably more exciting symptoms than a tripped RCD.

Bad weather means rain. This might improve local earthing, which I
can't see as a problem. Maybe there's poor or damaged wiring or a
faulty appliance that gets wet somewhere that causes a leak to earth
from live, which *would* trip an RCD.

--

-Pip

El Wed, 26 Oct 2022 10:29:26 +0100, Pipl escribió:

> Bad weather means rain. This might improve local earthing, which I can't
> see as a problem. Maybe there's poor or damaged wiring or a faulty
> appliance that gets wet somewhere that causes a leak to earth from live,
> which *would* trip an RCD.

<or neutral to earth>

That's what I'm guessing. There is wiring outside that goes to a
(currently unused) backup water pump and the pool shed (pump, heat pump
etc). This is isolatable, but as yet, I haven't been able to reproduce
the fault, as it only happens when there are guests there. We also get
lots of power cuts here, so the tripping and rearming looks just like one
of those.

I'm guessing that the integrity of the DC wiring on the roof couldn't
have any influence.

--
Paul.

https://paulc.es/elpatio