Increasing inverter high voltage setpoint

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electrofelon said:
You typical 240 single phase inverter comes with a high setting of 264. Can I go higher than that?
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Parts of South America use 220Y127 as a nominal standard (Brazil I think) and I have seen "208/120" systems operating at 220/127, I remember becasue back in the incandescent lightning days they would use 130V light-bulbs.
I would bet inverters made for the 'Americas' (60 /hz) might be able to go to 267 with programing.
 
So an update: just an hour ago I called SMA and they said all I had to do to get the "grid guard access code" was to sign up for an online SMA support account, and then I could request it right on the website. It took like 5 minutes, it didn't have to approved or anything. I didn't have to explain what I wanted to change or why. I just had to check a box attesting I was qualified. That was sure easier than I thought.
 
Ok, another update. Went to the site today to increase that set point. I enter the grid guard code and it takes it, but I can't for the life of me figure out where that voltage setting is. Call SMA......what a crapshow....first guy asks what I have the grid set as in the inverter. I say UL1741/2016/120. He says the high voltage with that is 229 volts and it needs tone set to UL1741/2016/240. He is just playing wrong that is not correct. We call back and get another guy, end up on the phone with him for an hour.

"Who told you that high voltage setpoint could be changed? Someone at SMA?" He asks.

Ummm, "well I guess no one has said specifically it can be done with this inverter, but I have heard of it being done in general and i'm pretty sure it's a thing....". I say.

He said it is not changeable and tells me to put the inverter in Island mode as a temporary fix. What the hell is that? Well I do it and the inverter does still work, but not really sure what that does to the voltage set points. Then he basically said it's the grid that's the problem and directs us to the German version (????) of the SMA web site to look for some equipment that might work. At that point it was just getting so bizarre we just kind of got off the phone.

So I dabble around some more and actually do find where what I think is the upper voltage tripping set point. It's a bit confusing because when you are set to the UL 1741 / 2016/120 grid which is what you use for 120 240 split phase, everything is half. In the field I am thinking is the correct one is called "lower maximum voltage" or something like that, it's set at 132, so I change it to 134.

So this whole time I never did see the voltage get above 259, so I don't know if the inverter is just a little touchy or not working quite right or the voltage does sometimes creep up to 264. I'll go back in a week or so and see if there any more error codes for over voltage.
 
So one specific question:.

My understanding is I could remove the neutral conductor and change the grid setting to UL 1741 / 2016/240. Is there any reason to do or not do that? In the manual they say that is for "240 Delta" and conductors used are L1 &L2. Note this is what the first tech support guy told me to do, but I don't really fully trust him or know what that would accomplish.
 
electrofelon said:
So one specific question:.

My understanding is I could remove the neutral conductor and change the grid setting to UL 1741 / 2016/240. Is there any reason to do or not do that? In the manual they say that is for "240 Delta" and conductors used are L1 &L2. Note this is what the first tech support guy told me to do, but I don't really fully trust him or know what that would accomplish.
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Don't blame me if this is wrong, but I think this is generally fine. They call it Delta because it's intended to be used when you have multiple single phase inverters connected to different phases on a high-leg delta, in which case for some phases monitoring to neutral is not helpful. The potential reasons not to do it are: 1) if you don't know what you're doing you could connect it to a 208V source, which I think is not a concern in your case, and 2) if the split-phase voltage becomes unbalanced (e.g. transformer failing) the system might stay on when that wouldn't be beneficial.
 
jaggedben said:
Don't blame me if this is wrong, but I think this is generally fine. They call it Delta because it's intended to be used when you have multiple single phase inverters connected to different phases on a high-leg delta, in which case for some phases monitoring to neutral is not helpful. The potential reasons not to do it are: 1) if you don't know what you're doing you could connect it to a 208V source, which I think is not a concern in your case, and 2) if the split-phase voltage becomes unbalanced (e.g. transformer failing) the system might stay on when that wouldn't be beneficial.
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That makes sense. My reasoning was it would indeed work fine because they aren't specific about the grounding arrangement or which phases to connect to which implies it doesn't matter. Next time I might set it up as "240 Delta" and not run the neutral, just so I don't have to run the neutral if nothing else
 
electrofelon said:
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.
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Every 240 volt inverter I've worked on could be set to have an upper range of 264 volts. It only sounds scary.
 
electrofelon said:
Yeah 264 is the default, we are talking about raising it higher than that
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I don't remember how we controlled the upper voltage window, in the sense of it even being adjustable. Most of those values were hard-coded, and only the things that were supposed to be adjustable were adjustable. Remember that sometimes just because you enter a value doesn't mean someone like me hasn't written the code to silently ignore the value if its too high.

The other issue, and this is my favorite story of dealing with long distribution lines in Australia, is the inverter hardware itself may not be able to tolerate the higher output voltage. That is, the capacitors used to store the charge which is going to be converted to the output wave form may not have either a high enough voltage rating (well above the peak instantaneous voltage, not the RMS voltage) to deliver current at the peak, or there may not be enough storage capacity to avoid distortion.

If you ARE able to set the upper voltage window you may have to prove the output isn't clipping anyway, in which case you may well be out of spec for what you're supposed to be delivering. You may also risk equipment damage (both generation and utilization) and voiding some warrantees.

TL;DR: If SMA will let you do it, great. Just watch out for it not working properly in the long run.
 
tallgirl said:
Remember that sometimes just because you enter a value doesn't mean someone like me hasn't written the code to silently ignore the value
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🤬

The other issue, and this is my favorite story of dealing with long distribution lines in Australia, is the inverter hardware itself may not be able to tolerate the higher output voltage. That is, the capacitors used to store the charge which is going to be converted to the output wave form may not have either a high enough voltage rating (well above the peak instantaneous voltage, not the RMS voltage) to deliver current at the peak, or there may not be enough storage capacity to avoid distortion.

If you ARE able to set the upper voltage window you may have to prove the output isn't clipping anyway, in which case you may well be out of spec for what you're supposed to be delivering. You may also risk equipment damage (both generation and utilization) and voiding some warrantees.

TL;DR: If SMA will let you do it, great. Just watch out for it not working properly in the long run.
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As I said, I think I found the correct field and was able to raise it, but I didn't really have any way to test it. I may play around on my system, because I have the same inverters and I have transformers with taps so I can get the voltage up "too high" and see if the setting indeed works. I believe the menu provided a range of possible values, and the highest was 280. I just went up four volts to 268.
 
Another update. So good news, that inverter seems to be holding, but now the second inverter is getting some grid over voltage errors. I should have raised that one too, not sure what I was thinking in hindsight, but this confirms everything is working as it should and the settings were changed.
 
Okay another update. Apparently the power company found a bad voltage regulator and just replaced it. Where before the voltage at the array would typically hover in the high 250s, and of course peak up to 264, it's actually down in the high 230s now,. Now it's a little too low!
 
electrofelon said:
Okay another update. Apparently the power company found a bad voltage regulator and just replaced it. Where before the voltage at the array would typically hover in the high 250s, and of course peak up to 264, it's actually down in the high 230s now,. Now it's a little too low!
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There’s a trick and almost an art to setting the controls up correctly for the MANY different types of regulators. If it’s too low my bet is the guy that set it up doesn’t have something right.
GENERALLY speaking you set it for 123 with a 2V bandwidth.

But then it gets tricky…Rs and Xs may or may not be entered nor wanted, A Howard is normal closed on N, GE is normal open on N. Then there are Siemens, allis chalmers regulators, siemen allis regulators, Inverted vs straight, along with the ”U2” PT and the second “P2” pt that may or not be in there. The voltages on the PTs are all over the place and are noted on the control panel box data plate.
And it could be he simply put the control back in the new one without checking any settings.

All ours are monitored through SCADA and send me an email if they burp wrong….
 
Hv&Lv said:
There’s a trick and almost an art to setting the controls up correctly for the MANY different types of regulators. If it’s too low my bet is the guy that set it up doesn’t have something right.
GENERALLY speaking you set it for 123 with a 2V bandwidth.

But then it gets tricky…Rs and Xs may or may not be entered nor wanted, A Howard is normal closed on N, GE is normal open on N. Then there are Siemens, allis chalmers regulators, siemen allis regulators, Inverted vs straight, along with the ”U2” PT and the second “P2” pt that may or not be in there. The voltages on the PTs are all over the place and are noted on the control panel box data plate.
And it could be he simply put the control back in the new one without checking any settings.

All ours are monitored through SCADA and send me an email if they burp wrong….
Click to expand...
Yeah I imagine..... My partner on this project mostly dealt with the power company guy, so this is all secondhand. They said it was a bad actuator, which I is assume is the thing most likely to go wrong on these things. I don't know if they just replaced the actuator or the whole unit..... I am guessing the latter and they send the whole unit out for repair/rebuild.
 
Hv&Lv said:
All ours are monitored through SCADA and send me an email if they burp wrong….
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And that's what I find odd. Even if these aren't networked back to mission control, you would think they would have some program of going out and checking and retrieving the data on some regular basis. Who knows how long this thing hadn't been working for. It seems the problem was only noticed because we installed a PV system.
 
electrofelon said:
Yeah I imagine..... My partner on this project mostly dealt with the power company guy, so this is all secondhand. They said it was a bad actuator, which I is assume is the thing most likely to go wrong on these things. I don't know if they just replaced the actuator or the whole unit..... I am guessing the latter and they send the whole unit out for repair/rebuild.
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Bad actuator??? These things have LOTS of moving parts. Im not sure what they are calling an actuator.
Along with SCADA ours are visually inspected monthly
 
Hv&Lv said:

Bad actuator??? These things have LOTS of moving parts. Im not sure what they are calling an actuator.
Along with SCADA ours are visually inspected monthly
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Okay, wow. I admit I don't know much about these. I thought it was just a trash can with a few coils of Romex, a wiper contact and an actuator filled with waste motor oil...😂 Apparently they're a lot more complicated than I thought.
 
electrofelon said:
Okay, wow. I admit I don't know much about these. I thought it was just a trash can with a few coils of Romex, a wiper contact and an actuator filled with waste motor oil...😂 Apparently they're a lot more complicated than I thought.
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I have saw many that were just that, a giant trash can after a bad lightning storm or a contact goes bad or gets stuck between steps.
 
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