Net Metering: Phase Matching for Solar Panels

[rollingstein]

I was reading up on net metering, where the electric utility allows one to feed back excess generation by solar panels etc. onto the distribution network.

http://en.wikipedia.org/wiki/Net_metering

One question I had is, is it fairly easy to match phase for such inverters with the grid? How do they do it. These seem pretty small domestic units.

http://en.wikipedia.org/wiki/File:Feed-in_Tariff_meter_connections.jpg

 

[UltrafastPED]

They contain special circuitry to precisely match the voltage and frequency of the grid. IEEE 1547 is the standard which describes the requirements and testing: http://grouper.ieee.org/groups/scc21/dr_shared/

Here is some information on grid-tie inverters:
http://en.wikipedia.org/wiki/Solar_inverter

And a readable technical report with cost estimates for entire systems:
http://www.eecs.berkeley.edu/~phucle/EE_290N/290N_report.pdf

 

[dlgoff]

Another thing to consider about these inverter applications (i.e. grid ties) is safety. If the inverter doesn't detect the correct voltage from the utility, say during a power outage, they open the disconnect. You wouldn't want to hurt some utility worker doing work on a line they thought wasn't energized.

 

[rollingstein]

Thanks for the info.

I learned a lot of new stuff, especially the islanding bit.

The documents seem a bit light on how exactly the phase matching is done. I'm intrigued because so far I was under the impression that precise phase matching was an expensive & time consuming activity & so am surprised that a $200 box can take care of it.