[RE-wrenches] Enphase "AC Frequency out of Range"
penobscotsolar at midmaine.com
penobscotsolar at midmaine.com
Thu Feb 7 15:19:42 PST 2013
Enphase engineers have contacted my client and will do a preliminary test
of the Enphase fix sometime next week to see if it is effective. They will
be using a Hioki PQA during the testing. I applaud Enphase for staying on
this and even if this first fix needs some tweaking, I am confident they
will make it work.
Daryl DeJoy
NABCEP Certified PV installer
Penobscot Solar Design
> I see in your signal capture that the firing angle is earlier than mine
> so that it doesn't (always) go across the zero crossing. From what the
> utility system operator here has told me about their TWACS, the firing
> angle is adjustable from about 5 to 30 degrees before the zero crossing.
> Supposedly, they increase the firing angle to get a stronger signal from
> sites that are hard to reach.
>
> Kent Osterberg
> Blue Mountain Solar, Inc.
> www.bluemountainsolar.com
>
> On 2/7/2013 2:13 PM, Nick Soleil wrote:
>> 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
>> <mailto: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 <http://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
>>> <mailto: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>
>>> > [mailto:re-wrenches-bounces at lists.re-wrenches.org
>>> <mailto:re-wrenches-bounces at lists.re-wrenches.org>] On Behalf
>>> Of
>>> > penobscotsolar at midmaine.com
>>> <mailto: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 <http://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
>>> <http://www.independentpowerllc.com>
>>> >>
>>> >> Vermont Solar Partner
>>> >>
>>> >> 25 Years Experience, (802) 888-7194
>>> <tel:%28802%29%20888-7194>
>>> >>
>>> >>
>>> >>
>>>
>>>
>>
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>>
>>
>> --
>>
>> Cordially,
>>
>> *Nick Soleil*
>>
>> *Field Applications Engineer
>> *
>>
>> *Enphase Energy*
>>
>> Mobile: (707) 321-2937
>>
>>
>> **
>>
>> *Enphase Commercial Solar.* *Limitless.*
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>>
>> *
>> *
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>>
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>>
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>>
>> www.enphase.com <http://www.enphaseenergy.com/>
>>
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>>
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>>
>> E: nsoleil at enphaseenergy.com <mailto:nsoleil at enphaseenergy.com>
>>
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>>
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