On Apr 13, 8:59*pm, Home Guy wrote:
harry wrote:
A typical residential PV system might be, say, 5 kw. *At 120
volts, that's about 42 amps. *How are you going to push out
42 amps out to the grid? *You're not going to do it by matching
the grid voltage. *You have to raise the grid voltage (at least
as measured at your service connection) by lets say 1 volt.

Bad analogy. The 1V will be lost in the internal resistance of the
inverter connection, which is much higher than that of the grid.

What happens to the "say" 1 volt. * It is only a local thing because
the utility drops it's output by 5Kw.

I doubt that the regional sub-station is going to do that.

Sure, there will be different current flow around the system
but nothing that can't be handled.

I didn't say that it couldn't be handled.

I'm saying that a small-scale PV system is going to raise the local grid
voltage for the homes connected to the same step-down distribution
transformer. *All the linear loads on the local grid will consume the
extra power (probably about 250 to 500 watts per home, including the
house with the PV system on the roof). *The extra 250 to 500 watts will
be divided up between the various AC motors (AC and fridge compressors,
vent fans) and lights. *They don't need the extra volt or two rise on
their power line supply - the motors won't turn any faster and the
lights will just convert those extra watts into heat more than light
output. *

The home owner with the PV system will get paid 80 cents / kwh for the
40-odd amps he's pushing out into the grid, but that energy will be
wasted as it's converted disproportionately into heat - not useful work
- by the linear loads on the local grid.

I don't know why you rabbit claiming it doesn't work when it
clearly does.

I don't see a rabbit around here.

I'm not claiming that pushing current into the local grid by way of
raising the local grid voltage doesn't work.

You are claiming that any electricity produced by PV arrays that
goes onto the local grid just gets wasted because putting it on
the grid raises the voltage a tiny amount. I think that's what
he meant by saying "it doesn't work". That is you're saying
that PV arrays that have net current flowing into the grid
don't work, because the energy somehow just gets
dissapears.

There is SO much wrong in your analysis, that I don't know
where to begin. But here's a start. You claim that with
a slightly higher voltage, an AC motor in an HVAC
compressor won't turn any faster and hence the additional
power is wasted. What you've completely overlooked is
that power is P=VI, or power is voltage times current.
Give that motor an extra half a volt and I'll bet it's current
decreases by a corresponding amount.



I'm claiming that there won't be a corresponding voltage down-regulation
at the level of the neighborhood distribution transformer to make the
effort worth while for all stake holders.

As Bud said a while back, you're new analysis must be devastating to
all the power companies in the world.