[RE-wrenches] XW / Wind problem to be fixed by firmware update

[Mark Edmunds]

Hi Matt,

 

This setup just had  a diversion load that kicked in at a high voltage -
some kind charge controller that regulated the battery V likely would
stabilize the system.

 

The XW max sell amps is configurable, and turning that down can help in
a situation like this too.

 

Mark

 

 

 

Mark Edmunds
Director Engineering 
Residential Renewable Energy Markets 
Xantrex Technology Inc. 

p. 604.422.2609 
f.  604.420.1591 
E-mail: mark.edmunds at xantrex.com 
Website: www.xantrex.com <http://www.xantrex.com>  



 

 

 

 

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Matt
Tritt
Sent: Friday, January 16, 2009 6:54 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] XW / Wind problem to be fixed by firmware
update

 

Mark,
 Since what I mainly do is small wind related, this thread has me a
little concerened. Is this application receiving AC in a' la SunnyIsland
style, via another grid-tie inverter, or is the battery being charged
via a charge controller? Lacking theSMA technology that controlls
battery voltage and the "sell" function in a little different way,
shouldn't this system be configured in the second manner, that is
charging the batteries through a charge controller and diversion
resistor? If it were set up this way, would you still have this problem,
or is the battery just so small that the voltage falls precipitously as
soon as sell kicks in? I thought that there is a 5 minute wait period
prior to connecting to the grid anyhow, so shouldn't things even out
during that hysteresis?

Is there a configurable setting on the sell function that might allow
some lattitude in the amps going to the grid, or is it pedal to the
metal, regardless? If there is no control over the sell amps, seems to
me that would be a good idea.

Matt T

Mark Edmunds wrote: 

Hi Wrenches -

 

Just to clarify on this a bit... When we designed the XW we were always
assuming there would be some sort of voltage regulation on the input to
the batteries, either with a PV MPPT controller or a diversion regulator
for wind and uHydro systems. So hence while the unit does try to
regulate the battery voltage while selling power to the grid it does
take some time when in sell mode to make sure everything is stable and
compliant  with the UL1741 limits before actually starting to transfer
power.

 

With a typical set up this is just fine, but obviously with a wind
system like this the delay allows the voltage to rise to the point the
inverter thinks it has a lot of power to sell, and with smaller battery
bank sizes quickly pulls the voltage back down to the point it stops
selling. 

 

As mentioned below we think we can speed this start of selling to the
grid when battery voltage rises past the Grid Support Voltage setting,
which should help smooth out this sort of situation. Initially we will
test this in the lab and at  a few sites to ensure we get good
performance, then will roll the change into new units. This all may take
longer than a few weeks, but we will do our best!

 

Yours for a windy future...

 

Mark

 

 
 
  
 


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