Grid connect question

[Phil Allison]

"swanny"

How do the solar panel grid-tie inverters behave when the section you
are feeding is isolated from the grid (say during a fault)? Do they feed
the fault current? Do they isolate (for safety reasons) until the grid
is reconnected and the inverter re-synchronised?

http://en.wikipedia.org/wiki/Grid-tie_inverter#Typical_operation



..... Phil

 

[kreed]

On Aug 16, 12:15 pm, swanny <swa...@nospam.net> wrote:

On 10/08/2011 11:43 AM, Phil Allison wrote:



** Hi all,

when a householder decides to "go solar" and get PVs plastered all over
their roof  -  an electrician installs a converter box so power can be fed
back into the grid on sunny days.

My question is does the relevant energy supplier have to be informed of this
?

Do they keep a record of all home solar installations ?

If for no other reason, so they will not be alarmed by the sudden drop in
consumption as shown on the customer's meter.

.....  Phil

How do the solar panel grid-tie inverters behave when the section you
are feeding is isolated from the grid (say during a fault)? Do they feed
the fault current? Do they isolate (for safety reasons) until the grid
is reconnected and the inverter re-synchronised?

They must disconnect within 2 seconds. They use elaborate means to
detect whether the grid is "real" or not and act accordingly
Look up "anti islanding"

According to a readers letter in last month's silicon chip, 2 methods
used are for the inverter to try and manipulate the voltage or the
frequency of the mains slightly. This won't be possible with the grid,
but will be with other inverters or small generators.


I would also think that even in the absence of the above, the inverter
would make up its own mains waveform by sampling the waveform of the
incoming mains. If you cut the mains supply at the pole transformer
for a block, and there were a lot of solar inverters on block still on-
line, I would think the inverters (more powerful ones?) would try and
sample each others frequencies, causing them to raipdly "chase" each
other up or down in frequency. Once the frequency was out of range,
they would all be designed to shut off. ?

 

[terryc]

swanny wrote:

Not really, the ATO regards it as assessable income.

Then the solar panels become a cost of earning that income and are able
to be written off or depreciated against it?

Catch 22. if you take the government handouts, then you are not a
business. The high feed in rate is only available to residential
properties. For anything else you have a truck load of paperwork to
plough through and you need to sell your production yourself.
>

 

[terryc]

swanny wrote:

Do they isolate (for safety reasons) until the grid
is reconnected and the inverter re-synchronised?

Yes. All this and more is o the various websites.

 

[terryc]

kreed wrote:

On Aug 17, 12:17 pm, terryc <newsninespam-s...@woa.com.au> wrote:
swanny wrote:
Not really, the ATO regards it as assessable income.
Then the solar panels become a cost of earning that income and are able
to be written off or depreciated against it?

Catch 22. if you take the government handouts, then you are not a
business. The high feed in rate is only available to residential
properties. For anything else you have a truck load of paperwork to
plough through and you need to sell your production yourself.



what does that have to do with depreciating an asset that produces
assessable income ?

It is explained above. Had you read the ATO directives(private rulings)?

 

[kreed]

On Aug 17, 12:17 pm, terryc <newsninespam-s...@woa.com.au> wrote:

swanny wrote:
Not really, the ATO regards it as assessable income.

Then the solar panels become a cost of earning that income and are able
to be written off or depreciated against it?

Catch 22. if you take the government handouts, then you are not a
business. The high feed in rate is only available to residential
properties. For anything else you have a truck load of paperwork to
plough through and you need to sell your production yourself.

what does that have to do with depreciating an asset that produces
assessable income ?

 

[kreed]

On Aug 18, 10:15 am, terryc <newsninespam-s...@woa.com.au> wrote:

kreed wrote:
On Aug 17, 12:17 pm, terryc <newsninespam-s...@woa.com.au> wrote:
swanny wrote:
Not really, the ATO regards it as assessable income.
Then the solar panels become a cost of earning that income and are able
to be written off or depreciated against it?
Catch 22. if you take the government handouts, then you are not a
business. The high feed in rate is only available to residential
properties. For anything else you have a truck load of paperwork to
plough through and you need to sell your production yourself.

what does that have to do with depreciating an asset that produces
assessable income ?

It is explained above. Had you read the ATO directives(private rulings)?

No, but I will put it to my accountant at tax time.