Chris,
I just read a white paper on the Apparent Power site, and it appears
that they have an inverter that is one step smarter than your average
bear. The key quote:
"The inverter changes the DC input from the solar panels to AC, senses
the phase angle lag or lead on
the output line, and compensates by changing the phase angle of its
output current with respect to the
grid voltage, until the current and voltage are in-phase."
So it can sense how far off the voltage and current curves are and push
in a wave form combo that attempts to get the grid waveform back to
unity power factor. How successful it would be depends on the size of
the solar/inverter array compared to the other loads and generators on
the grid, but it is pushing in the right direction.
I used to work for Northern Power Systems in Waitsfield, VT. While I was
there they came up with a really smart inverter that did the same thing
only more so. I think the working name was the Power Router. It read the
grid waveform about 1000 times per second and modified its output at the
same rate to attempt to create a perfect unity factor sine wave on the
line. With enough Power Routers on an isolated grid you could see
garbage wave turned into lab grade sine wave. Sadly, it never became a
product.
This technology is more simplistic, but I'd say you have a good case to
bring to your utility. Send their engineers to the Apparent Power
website and let them geek out with the white paper:
http://www.apparent.com/downloads/TheMathematicsOfDynamicPowerManagementOnTheGrid.pdf
Remember that with utilities it's always a fight until they realize the
benefits.
Best,
Hilton Dier
Ray,
The idea that the utility in an island is seeing an advantage to
having PV on the grid is a huge concept for me. As I am based in a
small island with a utility that is scared of solar pv installations,
this concept is tremendous ammunition for me. I am also fascinated by
the idea of PV installations as a corrective power source, the
possibilities for this are tremendous.
If there is any more information anyone can offer on the impact of PV
on an island grid, I would be very interested to hear. I am going to
write an article on my blog and in print on how other islands are
benefiting from solar, so anything you can tell me will help to build
this story.
Chris Mason
--
Hilton Dier III
Renewable Energy Design
Partner, Solar Gain LLC
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