[RE-wrenches] Enphase "AC Frequency out of Range"

Thu Feb 7 14:13:32 PST 2013

Hi Kent and Wrenches,

Thanks for sharing that image.  We have some readings that we captured with
a Hioki Power Quality Analyzer.

I have this as a PDF, and can send it to anyone who would like to see this,
but have also attached a .tiff file that meets the file size requirements
of the list.  Send an email to me off-list if you'd like the PDF.

On Thu, Feb 7, 2013 at 10:21 AM, Kent Osterberg <kent at coveoregon.com> wrote:

>  The Aclara <http://www.aclaratech.com> TWACS<http://www.aclaratech.com/AclaraPLS/pages/default.aspx>signal that knocks the Enphase inverters off line is difficult to capture
> because it only last a few seconds every time the meter replies to a ping
> or data request. I did manage to capture it using Zelscope<http://www.zelscope.com/>with a long recording time. The attached image shows a pulse at the zero
> crossing of the ac waveform; some crossings don't have a pulse  - I think
> that is a binary zero and the pulse represents a one. The pulse does not
> change the ac frequency and has only a negligible effect on the rms ac
> voltage. However, the time between zero crossings is not always 16.67 ms.
>
> Messing with the zero crossing like that is an ugly thing to do to the ac
> voltage. Many things other than inverters can be messed up by this. It
> caused one of my digital clocks to run fast. Our local utility has had
> complaints about numerous other devices that it has messed up. I've got
> some SunnyBoy systems with remote monitoring that don't seem to be bothered
> by this signal. The Enphase inverters do not tolerate it. I'm glad to hear
> that Enphase is working on a fix and hope that it is rolled out soon.
>
> Kent Osterberg
> Blue Mountain Solar, Inc.www.bluemountainsolar.com
>
> On 2/5/2013 2:38 PM, Nick Soleil wrote:
>
>   Hi wrenches,
>
> The frequency out of range issue is being caused by some utility meter's
> communication "ping".  This ping is actually affecting the utility voltage
> and frequency, and can be viewed with a power quality analyzer.  It is
> highly likely that this is affecting a wide variety of utility-interactive
> inverters, but is only noticeable with the Enphase systems; due to the high
> level of visibility that our Enlighten monitoring and reporting provides.
>
>  These changes required that the software undergo a new certification
> process. We have completed our CSA certification of the new software, and
> are validating it's functionality before pushing out the solution to our
> entire population of microinverters.  We are in the process of beta testing
> the software fix, and are hoping to have this resolved in February.
>
>  Thank you for your patience as we work to resolve this issue.
>
>
> On Tue, Feb 5, 2013 at 9:24 AM, <penobscotsolar at midmaine.com> wrote:
>
>> Dave,
>>    It doesn't happen often, and the longest I've seen him stay "down" is
>> about a half hour, but it seems to get progressively worse as time goes
>> on for some reason (initially only the five minutes, but longer down
>> times lately). This particular customer is difficult and picky, to
>> boot. I hope yours is a bit kinder. Mine seems to think we did him an
>> injustice of monumental proportions.
>>    We have had the utility out there logging events, meetings with the
>> utility and another solar company in Maine to discuss all this, and
>> have kept Enphase in the loop throughout. Enphase has responded in a
>> responsible and reasonable manner throughout.
>>    If you want to discuss this with Enphase, call and ask for Bret. He's
>> the engineer I previously dealt with, although he is second tier, he is
>> accessible.
>>
>>
>>
>>
>> > Thanks Daryl. Does your system also sometimes stay off for longer
>> periods
>> > sometimes? My clients system can stay off for up to 64 minutes.
>> >
>> > Dave
>> >
>> > -----Original Message-----
>> > From: re-wrenches-bounces at lists.re-wrenches.org
>> > [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of
>> > penobscotsolar at midmaine.com
>> > Sent: Tuesday, February 05, 2013 12:01 PM
>> > To: RE-wrenches
>> > Subject: Re: [RE-wrenches] Enphase "AC Frequency out of Range"
>> >
>> > Dave,
>> >   We have been having the same problem with an Enphase system in Maine.
>> I
>> > have been dealing directly with the third tier engineers at Enphase and
>> > they
>> > are working on a software fix for this. The"event" itself is only a
>> > fraction
>> > of a second but IEEE requirements are that the inverter shut down for
>> five
>> > minutes. I only found out about this problem when it started for this
>> > customer. It sems that Enphase has already addressed the problem with a
>> > software fix for the M-190's. The M-215 fix should come, according to
>> > Enphase, by the end of March. It will be automatically downloaded
>> through
>> > the Enlighten router.
>> >    It's a known issue with Smart Meters with Enphase, but should be
>> > reconciled soon.
>> >
>> > Daryl DeJoy
>> > NABCEP Certified PV installer
>> > Penobscot Solar Design
>> > www.penobscotsolar.com
>> >
>> >
>> >
>> >> Wrenchsters,
>> >>
>> >>
>> >>
>> >> I have an Enphase 7.5kW system on a residence with utility Smart
>> >> Metering, both the PV Production Meter as well as the utility billing
>> >> meter being "read" every hour. This system has experienced many "AC
>> >> Frequency Out Of Range" events since the system was installed. Below
>> >> is copied the Enphase Event message. This particular event was for 5
>> >> minutes. Most of the events (all events are AC Frequency Out Of Range)
>> >> last 5 to 10 minutes but occasionally they have lasted from 45 minutes
>> >> to
>> > 64 minutes.
>> >>
>> >>
>> >>
>> >> My question is: Could the use of the smart metering increase the
>> >> likely hood that AC Frequency events happen? Or is this just a
>> >> coincidence and that we are dealing with fluctuating utility power AC
>> >> Frequency issues?
>> >>
>> >>
>> >>
>> >> <<
>> >>
>> >>
>> >>
>> >> Started on: Mon February 04, 2013 12:49 PM EST
>> >>
>> >> Cleared on: Mon February 04, 2013 12:54 PM EST
>> >>
>> >>
>> >>
>> >> Recommended action
>> >>
>> >>
>> >>
>> >> This condition should correct itself. No action is required.
>> >>
>> >> Details
>> >>
>> >>
>> >>
>> >> The microinverter reports that the frequency coming from the utility
>> >> is either too low or too high as specified by applicable regional
>> > standards.
>> >>
>> >>
>> >>
>> >> AC frequency is the frequency at which voltage varies on the utility
>> >> grid.
>> >> Frequency Out of Range events are usually transient and
>> >> self-correcting by the utility.
>> >>
>> >>
>> >>
>> >> When the microinverter detects an out of frequency condition, it must
>> >> remain offline until the utility has been within acceptable limits
>> >> continuously for a short period of time (seconds to minutes, varies by
>> >> region). If during that time the utility again exceeds or falls short
>> >> of acceptable limits, the five-minute timer must restart and the
>> >> microinverter may not begin producing power for an additional short
>> >> period following the last out-of-bounds condition.  >>
>> >>
>> >>
>> >>
>> >> Best,
>> >>
>> >> Dave
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> David Palumbo
>> >>
>> >> Independent Power LLC
>> >>
>> >> 462 Solar Way Drive
>> >>
>> >> Hyde Park, VT 05655
>> >>
>> >> www.independentpowerllc.com
>> >>
>> >> Vermont Solar Partner
>> >>
>> >> 25 Years Experience, (802) 888-7194 <%28802%29%20888-7194>
>> >>
>> >>
>> >>
>>
>>
>
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-- 

Cordially,

*Nick Soleil*

*Field Applications Engineer
*

*Enphase Energy*

Mobile: (707) 321-2937

**

*Enphase Commercial Solar.*
*Limitless.*<http://www.enphase.com/commercial?utm_source=email&utm_medium=sig&utm_campaign=Comm2012>

*
*<http://www.enphase.com/commercial?utm_source=email&utm_medium=sig&utm_campaign=Comm2012>

1420 North McDowell

Petaluma, CA 94954

www.enphase.com <http://www.enphaseenergy.com/>

P: (707) 763-4784 x7267

F: (707) 763-0784

E: nsoleil at enphaseenergy.com

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