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:aug...@luminalt.com] *Sent:* Monday, June 12, 2017 12:37 PM *To:* RE-wrenches <re-wrenches@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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