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

[Kent Osterberg]

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 <k...@coveoregon.com> wrote: The Aclara TWACS 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 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, <penobscotso...@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-boun...@lists.re-wrenches.org > [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of > penobscotso...@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 >> >> >> _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -- Cordially, Nick Soleil Field Applications Engineer Enphase Energy Mobile: (707) 321-2937 Enphase Commercial Solar. Limitless. 1420 North McDowell Petaluma, CA 94954 www.enphase.com P: (707) 763-4784 x7267 F: (707) 763-0784 E: nsol...@enphaseenergy.com  Certified Solar PV Installer #03262011-300 “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 This email message is for the sole use of the intended recipient(s) and may contain confidential and/or privileged information. If you are not an intended recipient, you may not review, use, copy, disclose or distribute this message. If you received this message in error, please contact the sender by reply email and destroy all copies of the original message.

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