Hi Dana, I¹m hearing that it ³should² be OK, but to CYA install a relay.
We just secured a third such system this one with the generator and transfer switch 200 feet away from the inverter. Installing a relay on this one would mean 200 feet of conduit through driveway and landscaping. Or, maybe a wireless connection......? This one is a small array (1.9 kW) and a large genny (~20kW), so I¹m inclined to think of the PV (if it even syncs with the generator) as offsetting the house load, and not capable of messing with the genny. I hope that¹s not just wishful thinking :) Thanks for the explanation. -Kelly On 11/20/08 12:07 PM, "Dana Brandt" <[EMAIL PROTECTED]> wrote: > Hey Kelly, > > I think that's probably the best solution. I don't think it should be > necessary with Sunny Boys in gridtied system, but it's certainly the safest > bet. I'm not sure if all SB's come with the right firmware, or if it's a > special option, but they can be programmed to allow for a wide grid frequency > window. This is used in the AC coupled arrangement with the Sunny Island. When > the Sunny Island's batteries are full it starts to raise the grid frequency > slightly. The SB's read this as an instruction to reduce their output and pull > their arrays off MPP. At a defined frequency, the SB's shut down entirely. > > So, the stories of SB's frying generators in off grid, AC coupled systems > makes me think that the tight frequency window required for grid-tied systems > had been replaced by the wider window used for communication with the Sunny > Island. It was one of the first prototypes of these systems so it might be a > little different now, but I installed a system that allowed the SI supported > grid to range from 50Hz all the way up to 54Hz before the SB's shut down. That > could allow quite a bit of backfeeding of the generator and might explain the > generators being fried in these SI/SB AC coupled systems. I would think that > with regular gridtied SB's they'd shut down before damaging the generator. > > Bottom line, though, I'd probably install the NC relay powered off the > generator input to be safe. > > Dana Kelly Keilwitz, P.E. Whidbey Sun & Wind, LLC Renewable Energy Systems NABCEP Certified PV Installer 987 Wanamaker Rd, Coupeville, WA 98239 PH & FAX 360-678-7131 [EMAIL PROTECTED]
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