Scot Arey wrote:
> "How did “module-level” shutdown get taken as gospel truth?? I’m thinking a Fronius Primo with its RSD Quattro device mounted on an > array rail meets current 2017 code." Mick here: The issue is that if a Fronius type PV "string" is interrupted at the edge of the array, one still has open circuit voltage on the string that's much higher than the 80 volt limit. The MLPE "module level power electronics"--whether they're microinverters or DC optimizers--snub any sum of AC or DC voltage below 80 when they're in shutdown mode. Both of those solutions also optimize to the level of individual PV modules & they provide granular metering of the energy deliveries--but I assume those benefits are of little value to the project you're planning, Scot. I don't know the availability status for Midnite's SOB "Shut Off Box", but this segments the PV string during shutdown & it gets the voltage below 80 without the expense of optimization & granular monitoring. There are still "electronics" behind each PV module because these shutoffs are triggered by radio but it's not MLPE in the usual sense & the cost is relatively low since all they're doing is opening contactors. I hope this reply is helpful. The Wrench List is The Bomb! Mick Abraham, Proprietor www.abrahamsolar.com Landline: 970-731-4675 Cell phone or for text messaging: 970-946-6584 ᐧ
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