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: [email protected] Website: www.xantrex.com <http://www.xantrex.com> From: [email protected] [mailto:[email protected]] 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 ________________________________ No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.176 / Virus Database: 270.10.8/1898 - Release Date: 1/16/2009 3:09 PM
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