[RE-wrenches] Apparent power

[Darryl Thayer]

The first thought that comes to mind is recative power is not real power, and is normally solved with pavsive devices like capacitor banks.  There are things like switchable capacator banks that canvary the reactive power by having diffreent amount of capacators to the line.  
 
So although I think inverters can reactive correction, why not use a capacitive device?   
Darryl
 

________________________________
 From: "boB at midnitesolar.com" <boB at midnitesolar.com>
To: RE-wrenches <re-wrenches at lists.re-wrenches.org> 
Sent: Saturday, February 4, 2012 8:05 PM
Subject: Re: [RE-wrenches] Apparent power
  



Sounds like a voltage source (and sinking) inverter to me.

These types can cause current distortion which the UL1741 / IEEE
    1547 specs try to prevent.

Apparent must be able to  turn that mode on and off I would
    imagine.  It's not too difficult to do.  No wonder
they talk about micro-grids.

The old Trace SW series was a voltage source inverter, even when
    grid tied and is basically why they had
to add that extra inductor box between SW and the grid when selling. 
    It could actually help the grid wave-
form voltage if it was distorted because of non-linear loads.

boB





On 2/4/2012 5:26 PM, Comet Systems wrote: 
As I understand the issue they claim to be able to address, the utilities often need a source of reactive power close at the system delivery points, the customer sites, because reactive power does not transmit well through the lines and transformers and uses up transmission resources better used for real power. The reactive power is used as a method of voltage control.  
>Therefore, it is reasonable that the utilities would pay a premium for a reactive power source which would be close to the customers and under their control. The idea has some merit and could be a significant direction for solar pv, but whether an electronic inverter can adequately generate reactive power at will, to act as a compensation device and whether that is the highest and best use for that power source is to be demonstrated. Interesting idea, though.
-- 
>Chris Mason 
>President, Comet Systems Ltd 
>
> 
>
>   
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