[RE-wrenches] Enphase "AC Frequency out of Range"
Kent Osterberg
kent at coveoregon.com
Thu Feb 7 14:36:57 PST 2013
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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>
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>
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>
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>
> E: nsoleil at enphaseenergy.com <mailto:nsoleil at enphaseenergy.com>
>
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