[RE-wrenches] Ginlong inverter current measured when no power being produced

[August Goers]

Hi All – I received a response off-list that helped point me in the right
direction. It appears that this phenomenon is due to imaginary current or
reactive power, especially when the inverters are producing little to no
energy. This article by Continental Control Systems, a common current
transformer manufacturer, seems to hit the nail on the head:



https://ctlsys.com/support/inverter-power-factor/



😊



August

Luminalt



*From:* August Goers [mailto:august at luminalt.com]
*Sent:* Monday, June 12, 2017 12:37 PM
*To:* RE-wrenches <re-wrenches at lists.re-wrenches.org>
*Subject:* [RE-wrenches] Ginlong inverter current measured when no power
being produced



Hi Wrenches,



We recently completed an experimental installation of small scale vertical
axis wind turbines. I’ve attached a couple of small pics for reference.
Yes, I know that vertical axis turbines have issues!



Anyway, two of the turbines are UGE VisionARI3 turbines with Ginlong
GCI-2.5K-2G-W-US inverters. We successfully commissioned the systems and
they are now running.



This site is installed partially to carefully monitor the wind and
production data so we have lots of datalogging equipment on site. We
noticed that the inverters are measuring about ~2.5 A of current flow on
the AC side (single phase 208 volt) even when the turbines are not
producing energy. Here is a little more detail:



The inverter connection to the AC-side electrical panel is via a 2-pole
breaker. We are seeing
current flowing in opposite directions in one wire (Line 1) compared to the
other
wire (Line 2). For instance, one wire might be showing 2.4A flow TO the
grid, while
the other wire shows 2.3A flow FROM the grid. This corresponds with a net
flow of about 0.1A TO the grid, which we are logging as the power produced
(in this case, about 0.1A * 208V = 21W). From what I can tell, this also
seems to roughly correspond to the power production shown on the inverter
LCD panel.





I know that this might be a bit of a long shot, but has anyone ever seen
inverter behavior like this in steady state? If you put a regular clamp
meter on line 1 or line 2, you get about 2.5 A of current flow which would
equate to ~ 500 watts. Bizarre.



Anyway, if anyone has a clue what this type of current flow reading means,
I’d be really curious to hear from you. We have a case into Ginlong but
their Chinese tech support hasn’t exactly been stellar.



Thanks,



August

Luminalt
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