Hi Troy,
Have you double checked that your grounding systems both in the house and at the inverters/array are all up to snuff? Sorry I can't offer any help with the inductance issue. Best, August *From:* [email protected] [mailto: [email protected]] *On Behalf Of *Troy Harvey *Sent:* Tuesday, February 11, 2014 5:45 PM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] Long transmission line inductance and LED light flicker Richard, *The system configuration is:* Approx 24.7kW of modules connected to: 2 x 9kW Sunnyboys 1 x 5kW Sunnyboys Plus 4 x 6kW sunnyislands, with 2 Parallel 48V Strings of (12 x 4V Surrettes ) using 350MCM cable *Wire* The wire is about 1000 feet long 350 MCM in a "twisted" bundle to this outbuilding *Conditions* The conditions were during the day with full sun, so during the test there is approx. 47kW of available inverter pointed at only >15 amps (120V) of load(!). The steady state conditions was a few LED lights, maybe 60 watts worth, plus a handful of vampire loads, maybe 100-200 watts total. When a pure resistance load, like a 1000W curling iron was turned on the lights would flicker. Since the lights flickered from a resistive load, but didn't stay dim, I assumed it was from a reactive-phase issues due to the transient turn-on - screwing with the LED dimmer circuits which are already doing a bit of magic to turn TRIAC waveforms into a DC constant current. thanks, Troy Harvey --------------------- Principal Engineer Heliocentric 801-453-9434 [email protected] On Feb 3, 2014, at 8:33 AM, Richard L Ratico <[email protected]> wrote: Hi Troy, I'm assuming this is off grid. Could you please provide details for the system (inverters, batteries, etc.). A single, sudden, 20 amp load is not necessarily small relative to the size of the system. Is the load 120V or 240 V? Dick Ratico Solarwind Electric --- You wrote: On Sun, Feb 2, 2014 at 4:39 PM, Troy Harvey <[email protected] >wrote: We've got a PV system that has long lines from the inverters to the house (1000 ft or so). While the wires are properly sized (2x350MCMs), it inherently has a lot of inductance due to the line-length. What We are noticing is that dimmable LED lights flicker anytime a new load turned on, even if that load is purely resistive and the overall current draw is small (20 amps or so). What I "think" is happening is the LED dimmer circuits get their cue from phase delays, and that the inductance of the line length causes some phase jitter everytime a load is applied - thus causing flicker. Has anyone dealt with this issue successfully (other than switching to incandescent lights)? Would a static capacitor bank at the house do the trick, or do we need some type of active PFC? And if static did you have any issues with constant power draw from the capacitors? Troy Harvey --------------------- Heliocentric --- end of quote --- _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
_______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
