SW Efficiency/ PWM Angle Adjustment [RE-wrenches]

[Joel Davidson]

I consulted to Anaheim Public Utilities for 18 months and had several discussions
with utility electrical engineers about PF devices to improve efficiency. Most
California municipal utilities can and want to use public benefits money to help
commercial customers improve efficiency because Kvars cost money. Geographical small
utilities and newer grids do not have PF problems like bigger and old sections of the
national grid. PF vendors regularly call on utilities and commercial customers to
sell their gadgets. While at Anaheim I told vendors if they could show a 5% savings
on a commercial customer's electric bill, the Utility could give the customer 75% of
project cost up to $100,000 to help pay for the materials and labor. We had no
takers. Before proposing capacitors to your local grid or to customers, find out if
they are having PF problems and if they are using PF devices now. Talk to the utility
electrical engineers with field knowledge, not the office guys.

"Mr. Sharkey" wrote:

>         Eric;
>
>         At this point, there are no inverters (that I know of) that correct for
> power factor beyond what the designers would consider "normal" and
> necessary for the inverter to react properly with the utility power to
> backfeed the system. It's an interesting concept that a grid-tied inverter
> might be capable of correcting the entire building's electrical service to
> unity, therefore making the building's consumption (or production) look
> like a pure resistive load (supply) to the utility. At this point, it's
> only a concept. It would probably take a lot of PV's and a really big
> intertied inverter to correct for the amount of reactance in a typical
> utility service load. That doesn't stop me from thinking about the
> possibility.
>
>         Earlier this year, at the Oregon Country Fair, I had this discussion with
> some of the Wrenches in attendance, and we thought it was a pretty flash
> idea at the time. Even just loading the AC line with capacitors would go
> some way towards improving the efficiency with, *or without* an intertied
> inverter in the system. I'd think utilities would be very interested in the
> possibility of subscribers being able to correct for PF losses in their
> distribution system. Maybe this is another tendril of the net metering vine
> that can crack the wall of utility resistance to intertied systems. A
> premium price paid for independently-produced, unity PF electricity! Yay!!
>
>         Extending the concept even farther: What if, instead of transformer-based
> inverters, we could develop capacitor-driven inverters? They would, by the
> laws of physics, be on the right side of the PF correction fence. This
> might be a better topic for HP's "The Wizard Speaks" column. Again, thought
> process need have no boundaries. Generally, it's been proven, if we as
> humans can think it up, (eventually) it becomes reality.
>
>         -S
>
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