Re: [RE-wrenches] Grid overvoltage and undervoltage issues on SMA install

[John Blittersdorf]

I agree with voltage drop,  I had two sb4000’s with this issue.  Power
company said it was on
Our side but I was sure it was the long run from the utility transformer.
They finally agreed and ran a heavier line.  Problem solved.  One
observation that was puzzling was that only one inverter would be off when
I arrived and it wasn’t always the same one.  When one shut off due to over
voltage, the voltage would drop and the second one would stay on.  Both had
the exact same upper voltage limit.

John B
On Thu, May 20, 2021 at 3:23 PM August Goers  wrote:

> Hi James -
>
> Is there a long run between the inverters and the point of
> interconnection? As others have pointed out, it appears that the symptoms
> you describe are voltage drop related. If the wire size is too small it
> will result in voltage at the inverters going up when current starts to
> flow. The inverters match the voltage at the utility point of connection.
> If, for example, the voltage at the main service panel is 240 volts and you
> have a 10% voltage drop due to undersized wires, you'd see 240 x 1.10 = 264
> v at the inverters. Sometimes this issue is compounded if the utility
> voltage is a little on the high side, which can happen at the end of the
> distribution lines.
>
> There could be other explanations as well.
>
> Best, August
>
> On Thu, May 20, 2021 at 10:25 AM Jerry Shafer 
> wrote:
>
>> Wrenches
>> Looks like the i verter is doing what it should 269 is out of range, what
>> is the at meter voltage, libe loss or very high output voltage, 41 volts
>> increase looks like resistance issues. More info would help, distance, wire
>> size etc.
>> Jerry
>> Jerry
>>
>>
>> On Thu, May 20, 2021, 9:52 AM James Reismiller 
>> wrote:
>>
>>> Hi Folks,
>>>
>>> I’m wondering if anybody has ideas on what could be causing grid
>>> over/undervoltage errors on an install we did about a year ago that now has
>>> these issues. The site is a 24 kW DC ground mount array with (3) SMA
>>> SB7.0-1SP-US-40 inverters. I’ve checked and done the following:
>>>
>>>1. Measured voltage min/max at inverter terminals and AC combiner.
>>>Min – 228VAC (with no inverter output) Max - 269 VAC (when inverter 
>>> trying
>>>to connect)!
>>>2. Had utility check service and transformer with load meter (with
>>>no PV running). No issues found and utility engineer stated he thinks 
>>> it’s
>>>on our side.
>>>3. Checked all AC connections including neutral (seemed like neutral
>>>issue) from inverters back to supply-side tap (fused disco).
>>>4. Changed SMA upper voltage window in grid guard settings to 272V
>>>max and 264V reconnection. This helped for a while but now is faulting
>>>again.
>>>
>>>
>>>
>>> Have any of you ran into this issue and how did you solve it? Or what’s
>>> the next thing to check?
>>>
>>>
>>>
>>> Thanks in advance!
>>>
>>>
>>>
>>> Be Well,
>>>
>>> James Reismiller
>>>
>>> He/Him/His
>>>
>>> NABCEP Certified Solar PV Installer®
>>>
>>> Abundant Solar
>>>
>>> 541-231-8072  xt. 3
>>>
>>> CCB#175919
>>>
>>> www.abundantsolar.com
>>> 
>>>
>>>
>>>
>>> "Don't get me wrong: I love nuclear energy! It's just that I prefer
>>> fusion to fission. And it just so happens that there's an enormous fusion
>>> reactor safely banked a few million miles from us. It delivers more than we
>>> could ever use in just about 8 minutes. And it's wireless!"
>>>
>>>
>>>
>>> ~William McDonough
>>>
>>>
>>> ___
>>> List sponsored by Redwood Alliance
>>>
>>> Pay optional member dues here: http://re-wrenches.org
>>>
>>> List Address: RE-wrenches@lists.re-wrenches.org
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Re: [RE-wrenches] Grid overvoltage and undervoltage issues on SMA install

[August Goers]

Hi James -

Is there a long run between the inverters and the point of interconnection?
As others have pointed out, it appears that the symptoms you describe are
voltage drop related. If the wire size is too small it will result in
voltage at the inverters going up when current starts to flow. The
inverters match the voltage at the utility point of connection. If, for
example, the voltage at the main service panel is 240 volts and you have a
10% voltage drop due to undersized wires, you'd see 240 x 1.10 = 264 v at
the inverters. Sometimes this issue is compounded if the utility voltage is
a little on the high side, which can happen at the end of the distribution
lines.

There could be other explanations as well.

Best, August

On Thu, May 20, 2021 at 10:25 AM Jerry Shafer 
wrote:

> Wrenches
> Looks like the i verter is doing what it should 269 is out of range, what
> is the at meter voltage, libe loss or very high output voltage, 41 volts
> increase looks like resistance issues. More info would help, distance, wire
> size etc.
> Jerry
> Jerry
>
>
> On Thu, May 20, 2021, 9:52 AM James Reismiller 
> wrote:
>
>> Hi Folks,
>>
>> I’m wondering if anybody has ideas on what could be causing grid
>> over/undervoltage errors on an install we did about a year ago that now has
>> these issues. The site is a 24 kW DC ground mount array with (3) SMA
>> SB7.0-1SP-US-40 inverters. I’ve checked and done the following:
>>
>>1. Measured voltage min/max at inverter terminals and AC combiner.
>>Min – 228VAC (with no inverter output) Max - 269 VAC (when inverter trying
>>to connect)!
>>2. Had utility check service and transformer with load meter (with no
>>PV running). No issues found and utility engineer stated he thinks it’s on
>>our side.
>>3. Checked all AC connections including neutral (seemed like neutral
>>issue) from inverters back to supply-side tap (fused disco).
>>4. Changed SMA upper voltage window in grid guard settings to 272V
>>max and 264V reconnection. This helped for a while but now is faulting
>>again.
>>
>>
>>
>> Have any of you ran into this issue and how did you solve it? Or what’s
>> the next thing to check?
>>
>>
>>
>> Thanks in advance!
>>
>>
>>
>> Be Well,
>>
>> James Reismiller
>>
>> He/Him/His
>>
>> NABCEP Certified Solar PV Installer®
>>
>> Abundant Solar
>>
>> 541-231-8072  xt. 3
>>
>> CCB#175919
>>
>> www.abundantsolar.com
>> 
>>
>>
>>
>> "Don't get me wrong: I love nuclear energy! It's just that I prefer
>> fusion to fission. And it just so happens that there's an enormous fusion
>> reactor safely banked a few million miles from us. It delivers more than we
>> could ever use in just about 8 minutes. And it's wireless!"
>>
>>
>>
>> ~William McDonough
>>
>>
>> ___
>> List sponsored by Redwood Alliance
>>
>> Pay optional member dues here: http://re-wrenches.org
>>
>> List Address: RE-wrenches@lists.re-wrenches.org
>>
>> Change listserver email address & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
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>> ___
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Re: [RE-wrenches] Grid overvoltage and undervoltage issues on SMA install

[Jerry Shafer]

Wrenches
Looks like the i verter is doing what it should 269 is out of range, what
is the at meter voltage, libe loss or very high output voltage, 41 volts
increase looks like resistance issues. More info would help, distance, wire
size etc.
Jerry
Jerry


On Thu, May 20, 2021, 9:52 AM James Reismiller 
wrote:

> Hi Folks,
>
> I’m wondering if anybody has ideas on what could be causing grid
> over/undervoltage errors on an install we did about a year ago that now has
> these issues. The site is a 24 kW DC ground mount array with (3) SMA
> SB7.0-1SP-US-40 inverters. I’ve checked and done the following:
>
>1. Measured voltage min/max at inverter terminals and AC combiner. Min
>– 228VAC (with no inverter output) Max - 269 VAC (when inverter trying to
>connect)!
>2. Had utility check service and transformer with load meter (with no
>PV running). No issues found and utility engineer stated he thinks it’s on
>our side.
>3. Checked all AC connections including neutral (seemed like neutral
>issue) from inverters back to supply-side tap (fused disco).
>4. Changed SMA upper voltage window in grid guard settings to 272V max
>and 264V reconnection. This helped for a while but now is faulting again.
>
>
>
> Have any of you ran into this issue and how did you solve it? Or what’s
> the next thing to check?
>
>
>
> Thanks in advance!
>
>
>
> Be Well,
>
> James Reismiller
>
> He/Him/His
>
> NABCEP Certified Solar PV Installer®
>
> Abundant Solar
>
> 541-231-8072  xt. 3
>
> CCB#175919
>
> www.abundantsolar.com
> 
>
>
>
> "Don't get me wrong: I love nuclear energy! It's just that I prefer fusion
> to fission. And it just so happens that there's an enormous fusion reactor
> safely banked a few million miles from us. It delivers more than we could
> ever use in just about 8 minutes. And it's wireless!"
>
>
>
> ~William McDonough
>
>
> ___
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches@lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
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Re: [RE-wrenches] Grid overvoltage and undervoltage issues on SMA install

[Barton Churchill]

You’ll need to either measure or calculate impedance from the inverters up to 
and ideally including the utility transformer. The most likely culprit are one 
or both are undersized.


From: RE-wrenches  on behalf of 
James Reismiller 
Sent: Thursday, May 20, 2021 10:52:06 AM
To: re-wrenches@lists.re-wrenches.org 
Subject: [RE-wrenches] Grid overvoltage and undervoltage issues on SMA install


Hi Folks,

I’m wondering if anybody has ideas on what could be causing grid 
over/undervoltage errors on an install we did about a year ago that now has 
these issues. The site is a 24 kW DC ground mount array with (3) SMA 
SB7.0-1SP-US-40 inverters. I’ve checked and done the following:

  1.  Measured voltage min/max at inverter terminals and AC combiner. Min – 
228VAC (with no inverter output) Max - 269 VAC (when inverter trying to 
connect)!
  2.  Had utility check service and transformer with load meter (with no PV 
running). No issues found and utility engineer stated he thinks it’s on our 
side.
  3.  Checked all AC connections including neutral (seemed like neutral issue) 
from inverters back to supply-side tap (fused disco).
  4.  Changed SMA upper voltage window in grid guard settings to 272V max and 
264V reconnection. This helped for a while but now is faulting again.



Have any of you ran into this issue and how did you solve it? Or what’s the 
next thing to check?



Thanks in advance!



Be Well,

James Reismiller

He/Him/His

NABCEP Certified Solar PV Installer®

Abundant Solar

541-231-8072  xt. 3

CCB#175919

[cid:image002.png@01D74D5D.CA065970]

www.abundantsolar.com<https://us-west-2.protection.sophos.com?d=abundantsolar.com&u=aHR0cDovL3d3dy5hYnVuZGFudHNvbGFyLmNvbS9hYnVuZGFudHNvbGFyL0hvbWUuaHRtbA==&i=NWY3Yjg4NTEwMTMzZWYwZjc4ZDZiZjM0&t=UlRoM0ZoK3IzYnVOempNMktCUE5mRHpIU25SdTczdmlXZEFHU1p4dmJTND0=&h=3abbc334e64d4897a91541320d5af142>



"Don't get me wrong: I love nuclear energy! It's just that I prefer fusion to 
fission. And it just so happens that there's an enormous fusion reactor safely 
banked a few million miles from us. It delivers more than we could ever use in 
just about 8 minutes. And it's wireless!"



~William McDonough


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Re: [RE-wrenches] Grid overvoltage and undervoltage issues on SMA install

[Kirpal]

Hey James,
Line 1 and Line 2 switched in the inverter combiner panel from any of the
inverters? ( line 1 connected to line 2 of inverter 2 or 3 or vice versa)?
Good luck!

Sunny Regards,
Kirpal Khalsa
Oregon LRT#25
Oregon Solarworks LLC
www.oregonsolarworks.com
541-299-0402


On Thu, May 20, 2021 at 9:52 AM James Reismiller 
wrote:

> Hi Folks,
>
> I’m wondering if anybody has ideas on what could be causing grid
> over/undervoltage errors on an install we did about a year ago that now has
> these issues. The site is a 24 kW DC ground mount array with (3) SMA
> SB7.0-1SP-US-40 inverters. I’ve checked and done the following:
>
>1. Measured voltage min/max at inverter terminals and AC combiner. Min
>– 228VAC (with no inverter output) Max - 269 VAC (when inverter trying to
>connect)!
>2. Had utility check service and transformer with load meter (with no
>PV running). No issues found and utility engineer stated he thinks it’s on
>our side.
>3. Checked all AC connections including neutral (seemed like neutral
>issue) from inverters back to supply-side tap (fused disco).
>4. Changed SMA upper voltage window in grid guard settings to 272V max
>and 264V reconnection. This helped for a while but now is faulting again.
>
>
>
> Have any of you ran into this issue and how did you solve it? Or what’s
> the next thing to check?
>
>
>
> Thanks in advance!
>
>
>
> Be Well,
>
> James Reismiller
>
> He/Him/His
>
> NABCEP Certified Solar PV Installer®
>
> Abundant Solar
>
> 541-231-8072  xt. 3
>
> CCB#175919
>
> www.abundantsolar.com
> 
>
>
>
> "Don't get me wrong: I love nuclear energy! It's just that I prefer fusion
> to fission. And it just so happens that there's an enormous fusion reactor
> safely banked a few million miles from us. It delivers more than we could
> ever use in just about 8 minutes. And it's wireless!"
>
>
>
> ~William McDonough
>
>
> ___
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
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[RE-wrenches] Grid overvoltage and undervoltage issues on SMA install

[James Reismiller]

Hi Folks,
I'm wondering if anybody has ideas on what could be causing grid 
over/undervoltage errors on an install we did about a year ago that now has 
these issues. The site is a 24 kW DC ground mount array with (3) SMA 
SB7.0-1SP-US-40 inverters. I've checked and done the following:

  1.  Measured voltage min/max at inverter terminals and AC combiner. Min - 
228VAC (with no inverter output) Max - 269 VAC (when inverter trying to 
connect)!
  2.  Had utility check service and transformer with load meter (with no PV 
running). No issues found and utility engineer stated he thinks it's on our 
side.
  3.  Checked all AC connections including neutral (seemed like neutral issue) 
from inverters back to supply-side tap (fused disco).
  4.  Changed SMA upper voltage window in grid guard settings to 272V max and 
264V reconnection. This helped for a while but now is faulting again.

Have any of you ran into this issue and how did you solve it? Or what's the 
next thing to check?

Thanks in advance!

Be Well,
James Reismiller
He/Him/His
NABCEP Certified Solar PV Installer(r)
Abundant Solar
541-231-8072  xt. 3
CCB#175919
[cid:image002.png@01D74D5D.CA065970]
www.abundantsolar.com

"Don't get me wrong: I love nuclear energy! It's just that I prefer fusion to 
fission. And it just so happens that there's an enormous fusion reactor safely 
banked a few million miles from us. It delivers more than we could ever use in 
just about 8 minutes. And it's wireless!"

~William McDonough

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