I have had to do this for some SMA inverters, and yes, SMA makes you jump through some hoops before they will give you access to that parameter, but no, I don't think I had to get anything from the POCO to show them.
And out of curiosity, did you try the power company route first and they were unwilling to do anything? Or was there a lot of drop in the customer wiring?
The issue was (and still is, I guess) the voltage rise between the building and the pole mounted transformer on cool clear days when the AC was not running; we raised the top operating voltage on the inverters and the problem went away.
I think what electrofelon was asking (and which I'm now curious about) is whether you tried to get the POCO to make some changes to their equipment to address the problem. E.g. if the voltage delta at the service panel, between "maximum load" and "minimum load / maximum PV export" was too large (comparable to exceeding the size of the inverter voltage window), then the POCO could have upsized the service drop to alleviate that. Or if the voltage delta was reasonable, but the range was offset from the inverter voltage window, they might have been able to change taps at the transformer to move the supply voltage lower to get it within the inverter window at both extremes.
Yeah. We were talking about high voltages back in this thread:
I understood what he asked and I answered it, I believe. No, we did not.
We did approach another POCO for a similar situation, to no avail. They said that their supply voltage, although somewhat high, was within their guaranteed window of operation, end of discussion. Our PV system used a stepdown transformer to convert the 480V inverter voltage to the 208V service voltage, so we buck-boosted it.
Do you know what these values are? I have looked but it doesnt seem black and white as there are several different ranges within the standard. You typical 240 single phase inverter comes with a high setting of 264. Can I go higher than that?
In the case I was discussing earlier where we upped the voltage window we had a bank of 10 SMA SB 7000's. On cool clear days when the customer was not running the AC and the PV system was running flat out, the inverters would start tripping off one at a time until the voltage rise would abate enough for the rest to keep running. It took us a while to figure out what was happening because the dropouts were different inverters every time it happened. Live and learn.
Do I understand correctly that the former, for utility maximum voltage at the point of service (presumably under no load/no export conditions), is 105% of nominal, and the latter maximum voltage, for the inverter, is 110% of nominal?
Maybe.
I'm looking at a data sheet for a family of inverters we use frequently - the SMA Core 1 series. The "stock" phase to neutral/ground voltage range is from 244V to 305V; 305V is 110% of 277V.
I am very confused about these values. I think there are different standards and in my experience most utilities will provide a much tighter voltage tolerance than +10%. I cant imagine a utility saying 264 is fine.
Right, my brief search on ANSI C84-1 for the utility service requirements was that the max voltage was +5% (or +5.8%, not sure when that would apply). And the inverter standard IEEE 1547 allows up to +10%. So that would give you at least 5% (or 4.2%) for your voltage rise, if the utility supply had zero impedance.
As far as I know, no. The system I am having issues right now, we have been going back and forth with the POCO guy a bunch, and he keeps saying stuff like "end of a long radial line", "not much other load around there....". But I'm just thinking well that is probably true, but as far as I know that is not a valid reason to do nothing. Im sure the POCO doesnt like it but it is what it is.
My guess would be yes, but only if you have an interconnection agreement.
