HBX together with grid-tie? (post-outage 5-minute UL1741 lockout)

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jnh
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Posts: 389
Joined: Fri Jun 01, 2007 11:56 am
My RE system: GVFX-3524, FM-80+FM-60, ~4.9kW PV in mixed panels on movable platforms, 415 Ah AGMs @ 24V, 350Ah @ 12V, Hub4, Mate, FNDC, Brultech GEM 32-ch AC datalogger, Midnite E-Panel, homebrew DC-DC crossfeed to 12V system, Honda EU-1000i, Iota DLS-27-25
Location: St. Augustine, FL, US

HBX together with grid-tie? (post-outage 5-minute UL1741 lockout)

Post by jnh » Fri May 15, 2020 12:31 pm

Has anyone experimented with using HBX mode as a fallback during times when grid-tie operation is locked out due to the UL1741-mandated 5 minute delay following a utility outage?

We had several brief outages today, over the span of a couple of hours, and it was annoying to see the system spend so much time under full sun, loafing along at minimal power output (covering only DC loads & battery float) while waiting for the grid-tie lockout period to expire.

I thought about trying to set up HBX, so the inverter would island itself under these circumstances and at least power its AC-Out loads autonomously, but wondered if having that enabled on the Mate might interfere with normal Grid-tie operation.

Will the 5-minute timer still count down after an AC DROP (grid source connected but not being passed through; AC IN indicator flashing), such that selling would promptly resume after going back to AC USE?

Also, I use the Auto Grid-Tie Control feature to ensure batteries receive a full charge each morning before selling is enabled, and would rather HBX not engage due to the expected rising battery voltage during that initial charge cycle, but expect this might be difficult to achieve using the Mate alone. Configuring my attached logging computer to send an AC DROP command at appropriate times would give more flexibility, but I still wonder how this would interact with the 5-minute lockout.

pss
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My RE system: 8330 watts in three strings, Flexmax 60 x 3, Radian 8048A, GSLC load center, Mate 3S, Hub 10.3, FN-DC and 900 Amp, 48V Trojan T105-RE battery bank.

Re: HBX together with grid-tie? (post-outage 5-minute UL1741 lockout)

Post by pss » Sat May 16, 2020 7:32 am

I don't think anybody has played around like you are asking. If I remember correctly, hbx is inverter stored, the other battery protection settings mate stored. Some settings cannot be used with hbx, they conflict. I keep hbx off. I program my battery connect and disconnect voltages. I keep auto grid tie off. If you increase your sell voltage, battery voltage will go higher before selling. Another option is to program to drop grid use for a period of time. This will allow batteries to top off. I drop from 4-9 PM and at 4 PM now my Batts get close to 59 to finish off. As for settings without hbx, the system, even with grid use dropped, will ignore you to protect the batteries and reconnect to the grid. Battery health is prioritized.

Mike Curran
Forum Emperor
Posts: 1556
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof:
- 8 (2x4) Evergreen 180's into one FM80 (2007/2020 repl'd MX60)
- 6 (2×3) ALEO S79-300's into one FM80 (2017)
- 2 grid-tied GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy ES maximizers on each PV module.

Westinghouse Solar - Barn roof: (2012)
- 30 (2x15) 235W panels with Enphase M215 microinverters, grid-tied, no longer AC- coupled

Outback Skybox - Barn roof: (2019)
- 14 (2x7) Talesun 275W (DC array input to SB charger)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W, Enphase M215 modules

All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: HBX together with grid-tie? (post-outage 5-minute UL1741 lockout)

Post by Mike Curran » Sat May 16, 2020 8:30 am

We had several brief outages today, over the span of a couple of hours, and it was annoying to see the system spend so much time under full sun, loafing along at minimal power output (covering only DC loads & battery float) while waiting for the grid-tie lockout period to expire.
Are you saying that your AC loads are not being supported during the 5 minute grid tie lockout period? Because in my experience, during and after a grid outage (while 5 minute lockout is in effect), my AC loads continue to be supported by my inverter. The lockout should only affect your system's ability to buy and sell from grid, not curtail your AC loads... :-k
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

fcwlp
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My RE system: GS8048A, FM80 w/3,600 W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed
I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: HBX together with grid-tie? (post-outage 5-minute UL1741 lockout)

Post by fcwlp » Sat May 16, 2020 11:19 am

jnh wrote:
Fri May 15, 2020 12:31 pm
We had several brief outages today, over the span of a couple of hours, and it was annoying to see the system spend so much time under full sun, loafing along at minimal power output (covering only DC loads & battery float) while waiting for the grid-tie lockout period to expire.

I thought about trying to set up HBX, so the inverter would island itself under these circumstances and at least power its AC-Out loads autonomously, but wondered if having that enabled on the Mate might interfere with normal Grid-tie operation.
My system and several of my customers are grid-tied with battery backup and do not use the HBX mode. The switchover on all systems is seamless with at most a slight flicker of lights. The only way I know the grid has gone down is if I get a text message from the power company or email from OpticsRE.

Some questions:
- What mode are you running in?
- In OpticsRE, on Mate3x - AC Input screen what is "AC Input" setting?
- In OpticsRE, on Inverter - What is AC Input Select Priority?
- In OpticsRE, on Inverter - What is Grid Input Mode?

jnh
Forum Guru
Posts: 389
Joined: Fri Jun 01, 2007 11:56 am
My RE system: GVFX-3524, FM-80+FM-60, ~4.9kW PV in mixed panels on movable platforms, 415 Ah AGMs @ 24V, 350Ah @ 12V, Hub4, Mate, FNDC, Brultech GEM 32-ch AC datalogger, Midnite E-Panel, homebrew DC-DC crossfeed to 12V system, Honda EU-1000i, Iota DLS-27-25
Location: St. Augustine, FL, US

Re: HBX together with grid-tie? (post-outage 5-minute UL1741 lockout)

Post by jnh » Wed May 20, 2020 1:30 am

Mike Curran wrote:
Sat May 16, 2020 8:30 am
We had several brief outages today, over the span of a couple of hours, and it was annoying to see the system spend so much time under full sun, loafing along at minimal power output (covering only DC loads & battery float) while waiting for the grid-tie lockout period to expire.
Are you saying that your AC loads are not being supported during the 5 minute grid tie lockout period? Because in my experience, during and after a grid outage (while 5 minute lockout is in effect), my AC loads continue to be supported by my inverter. The lockout should only affect your system's ability to buy and sell from grid, not curtail your AC loads... :-k
No, loads never lose power, so there's no trouble with that. They run fine from battery+PV power for the duration of the outage and ~12 sec after, then switch back to the grid, seamlessly enough that nothing is disrupted. (Returning to grid power is especially smooth since the inverter slews its frequency to achieve phase-lock during the 12-sec qualifying time.)

However, once the inverter accepts the AC input again and enters pass-through mode, being locked out from selling also means all AC-out loads are supported by utility power only for the next five minutes, since the GVFX has nothing like the "grid zero" mode of later models.

What I'd hoped for, to make use of otherwise-wasted PV power during these lockout delays would be something like

IF (outage cleared, but locked out from selling)
AND (available PV power >= current AC-Out demand)
THEN (DROP AC Input & remain off-grid for 5 minutes)

but after reading about HBX a little more, it doesn't seem flexible enough to work this way. Triggering the initial AC-Drop based on high battery voltage during the lockout period might work, but then wouldn't be able to switch back based on a time delay, remaining off-grid for the rest of the solar day.

The attached monitoring computer could potentially handle this, though, sending a manual AC DROP command to the Mate when these specific conditions exist (estimating potential PV generation based on battery voltage, production just prior to the outage, and/or current PV-Volts vs. typical MPPT point for that time of day), then simply waiting 5 minutes and commanding AC-USE.

The only question would be whether the inverter's 5-minute lockout period continues to count down when it detects good AC power, but is not using or passing it through to loads due to a manual DROP command, so that selling resumes promptly after a subseqeunt USE providing 5 minutes have elapsed, and the grid has remained stable. I vaguely remember experimenting with this years ago and finding the timeout seemed unaffected by DROP/USE state, but would need to verify this again.

And it may not really be worth coding this up, considering the rarity of grid disruptions forcing the inverter into lockout. After seeing several in one day last week, on a particularly windy day (suspecting tree branches were being repeatedly blown onto aerial lines somewhere), there have been no more short outages since.

jnh
Forum Guru
Posts: 389
Joined: Fri Jun 01, 2007 11:56 am
My RE system: GVFX-3524, FM-80+FM-60, ~4.9kW PV in mixed panels on movable platforms, 415 Ah AGMs @ 24V, 350Ah @ 12V, Hub4, Mate, FNDC, Brultech GEM 32-ch AC datalogger, Midnite E-Panel, homebrew DC-DC crossfeed to 12V system, Honda EU-1000i, Iota DLS-27-25
Location: St. Augustine, FL, US

Re: HBX together with grid-tie? (post-outage 5-minute UL1741 lockout)

Post by jnh » Wed May 20, 2020 1:43 am

fcwlp wrote:
Sat May 16, 2020 11:19 am
jnh wrote:
Fri May 15, 2020 12:31 pm
We had several brief outages today, over the span of a couple of hours, and it was annoying to see the system spend so much time under full sun, loafing along at minimal power output (covering only DC loads & battery float) while waiting for the grid-tie lockout period to expire.

I thought about trying to set up HBX, so the inverter would island itself under these circumstances and at least power its AC-Out loads autonomously, but wondered if having that enabled on the Mate might interfere with normal Grid-tie operation.
My system and several of my customers are grid-tied with battery backup and do not use the HBX mode. The switchover on all systems is seamless with at most a slight flicker of lights. The only way I know the grid has gone down is if I get a text message from the power company or email from OpticsRE.

Some questions:
- What mode are you running in?
- In OpticsRE, on Mate3x - AC Input screen what is "AC Input" setting?
- In OpticsRE, on Inverter - What is AC Input Select Priority?
- In OpticsRE, on Inverter - What is Grid Input Mode?
There's no issue with switching of loads between grid & inverter power during outages. That works flawlessly, with ac transfer delay dialed down to 2 cycles.

I was only looking to make use of wasted PV potential during a selling-lockout period by intentionally staying off-grid during that countdown time, whenever estimated available PV exceeds AC-Out loads (providing the 5-minute countdown continues during AC-Drop state, which needs to be tested). See my reply to Mike for details. It probably isn't worth the trouble of providing for this condition considering its overall rarity, despite that odd sequence of 4-5 power blinks last Friday over a few hours' time. If I do try for this, I realize now that HBX won't work, and the only way is probably to have my attached logging computer check for these specific conditions and send explicit DROP/USE commands back to the mate via serial.

My system is older, with an original oval Mate, so I don't/can't run OpticsRE, and the GVFX doesn't have selectable input modes like a Radian or FXR, but it operates in the rough equivalent to a Radian's GridTied mode, with AC Input kept on USE.

Mike Curran
Forum Emperor
Posts: 1556
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof:
- 8 (2x4) Evergreen 180's into one FM80 (2007/2020 repl'd MX60)
- 6 (2×3) ALEO S79-300's into one FM80 (2017)
- 2 grid-tied GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy ES maximizers on each PV module.

Westinghouse Solar - Barn roof: (2012)
- 30 (2x15) 235W panels with Enphase M215 microinverters, grid-tied, no longer AC- coupled

Outback Skybox - Barn roof: (2019)
- 14 (2x7) Talesun 275W (DC array input to SB charger)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W, Enphase M215 modules

All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: HBX together with grid-tie? (post-outage 5-minute UL1741 lockout)

Post by Mike Curran » Wed May 20, 2020 4:38 am

Consider that 5 minutes of lost selling represents about 408 watthours for your 4.9kw PV array. At $0.15/kwh, that's just about $0.06 worth of lost savings. Doesn't seem worth all the effort, no?
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

jnh
Forum Guru
Posts: 389
Joined: Fri Jun 01, 2007 11:56 am
My RE system: GVFX-3524, FM-80+FM-60, ~4.9kW PV in mixed panels on movable platforms, 415 Ah AGMs @ 24V, 350Ah @ 12V, Hub4, Mate, FNDC, Brultech GEM 32-ch AC datalogger, Midnite E-Panel, homebrew DC-DC crossfeed to 12V system, Honda EU-1000i, Iota DLS-27-25
Location: St. Augustine, FL, US

Re: HBX together with grid-tie? (post-outage 5-minute UL1741 lockout)

Post by jnh » Thu May 21, 2020 8:54 am

Mike Curran wrote:
Wed May 20, 2020 4:38 am
Consider that 5 minutes of lost selling represents about 408 watthours for your 4.9kw PV array. At $0.15/kwh, that's just about $0.06 worth of lost savings. Doesn't seem worth all the effort, no?
Fair point that even if these grid blips were happening regularly, it wouldn't make much sense to spend any time on this, or deal with the added complexity and possible failure modes. It was more my habit of obsessive optimizing than any concern for the economics.

I did go ahead and add a quick manual trigger to my Mate-logger code that will send a DROP command when requested, count down a specified number of minutes (default 5), then send a USE, so if I happen to notice another of these events I can invoke that without having to remember to switch it back, but it won't otherwise cause any trouble on its own. Could be occasionally useful for other situations too...

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