[RE-wrenches] Xslent?

[Dave Click]

Short answer: no, this product's reactive power generation will not 
affect you in the real world.

Long answer:
I don't see how their 6kVA system could outperform your 10kW system 
unless you're installing your system in the shade. This device seems to 
be quite limited- max VOC 42VDC, max input wattage 200W, max input 
short-circuit current 10A! And it appears to not have an internal 
GFDI(!), nor power line carrier, so you're running separate ethernet 
cable between the inverters.

As for the reactive power, a larger portion of future inverters will be 
able to supply complex power rather than just real power. However, an 
important part of that feature is that it will be dynamic- when the 
utility (or site) needs more reactive power, it can ask the inverter to 
adjust its output. I can't find anything in the documentation on this, 
but it appears from the description that this company plans for you to 
measure your site power factor, and then manually set these inverters to 
a certain power factor (presumably lower than the site PF to help adjust 
the site PF in the right direction). I don't know how power factor 
penalties are typically calculated; for the utilities that do actually 
charge this (not all do), would they look at the worst 15 minutes of the 
month? If so, I think it's safe to say that a 6kVA system of these 
inverters- which is presumably capable of peaking at 6 kVAR during about 
three hours of a nice day- will have minimal impact on that power factor 
penalty. And since the user manual tells you not to install more than 
30kW at a single interconnection point... how much do they really think 
they're helping?

So, the reactive power feature of this product may be worthwhile if your 
site only has power factor problems from about 10-2, only on sunny days, 
and you are on your computer at the site continuously adjusting the 
inverters' PF to ensure you're not overcompensating and making your site 
PF worse, and your utility penalizes for power factor, and your building 
power draw maxes out below the size of your PV system. To be really 
useful, VARs from inverters need to be dynamically configurable by some 
sort of software control so that you are always helping your site PF, 
and those VARs also should be available 24-7... and if the utility 
offers to pay you for your VARs, then they will also require the 
inverters to respond to utility requests for VARs (right after a power 
outage, for example, when a bunch of motors are trying to come back up 
to speed). And for this to really happen, we'll need a revised UL 1741. 
Maybe in 2015.

My $0.03.
DKC

August Goers wrote:
> Hi All -
>
> Have any of you heard of the Xslent XPX-A1000 microinverter?
>
> http://www.xetenergy.com/#Tab-2_link-1
>
> We're going up against them on a 10 kW system and I'm trying to figure out
> if their claims about producing reactive power mean anything to us in the
> real world. They are saying that their 6 kW system will outperform our 10
> kW system.
>
> I also noticed that their CEC efficiency is only 89%...
>
> Best,
>
> August
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