On Apr 11, 8:21*pm, The Daring Dufas
wrote:
On 4/11/2011 2:01 PM, David Nebenzahl wrote:
On 4/11/2011 10:32 AM harry spake thus:
The modern grid tie/connected "transformerless" inverter manipulates
the DC output from the panels so that they run on their "sweet spot"
ie the most efficient voltage and current. It self connects/
disconnects to the mains as and when there is sufficient light operate
the panels. I t uses the mains sine wave to generate it's own sine
wave on the AC side. The current delivered is indeed dependant on the
output voltage it dleivers to "push2 that current back into the
mains.
Bull****.
Bit on the topic here.
http://en.wikipedia.org/wiki/Kirchhoff%27s_circuit_laws
http://en.wikipedia.org/wiki/Grid_tie_inverter
Apparently you didn't even *read* that second article. It says:
The grid tie inverter must synchronize its frequency with that of the
grid (e.g. 50 or 60 Hz) using a local oscillator and limit the voltage
to no higher than the grid voltage.
Re-read that last phrase: "limit the voltage to no higher than the grid
voltage".
You don't "push" electricity from your solar installation into the grid
by raising the voltage, as someone here postulated. It just don't work
that way.
I remember a I & V limiting bench power supply I owned back when I
worked as a repair tech at a service depot. Under certain circumstances,
when I cranked the voltage control to raise the voltage, the voltage
stayed put but the current would rise. I wonder if that's the sort of
thing that happens when these grid connected inverters are used?
TDD- Hide quoted text -
- Show quoted text -
It's just another form of electricity generation in parallel with the
electricity grid. No different from any other form of generation. When
the PV array is generating the local voltage in the grid will rise a
little.
Or think of it another way. The current coming down the grid power
line will reduce as the PV panel takes up the local load, there will
be less voltage drop.
If the panel generates enough power the current in the grid will
reverse and the voltage close to the panel will be higher than the no
load grid voltage.