question

wehrner avatar image

3 phase Multi goes in overload when grid fails

Have 3x systems with similar behaviour. All 3x 3phase systems with Lithium Batteries in ESS mode. When grid fails, loadshedding, get inverter overload error and inverter switch off. Need to manual start with toggle switch. We can switch the main breaker off 100 times and no problem. When the council switch off the grid then overload. It sometimes is preceded with low battery voltage message VEBus but voltage does not drop under 53V. Most of the time it happens at night when there is very little load. Have quadruple checked wiring and comms cables and fuses etc. Have set the V mains disconnect higher to 200V on one system but still issue remains. Can have a look at system called Carreg Crescent for example. Our very experienced distributor for 12 years now also not sure what can cause this. Help would appreciated.

ESS
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Also what make of battery and how many in what configuration?

We have different 3-phase scenarios with the same issue. BYD and Pylontech. We have 28 kWh pylontech on 3x 10 kVA quattro and 13.8 kWh BYD on 3x 3kVA Multiplus II for example.

5 Answers
wesley-corbet avatar image
wesley-corbet answered ·

Hi @Wehrner@onesolar.co.za,

We are experiencing the same issue here in Australia.

Our system: On-Grid, 3 phase.

6 x Multiplus II 5's. Firmware: 2623469

Venus GX. Firmware: 2.42

12 x 2.5KWh BYD batteries.

We believe the grid voltage on phase 2 dipped under 'brown out' conditions which caused the system to shutdown completely and report error 17 (overload phase 2). The checks Victron suggest for this error checked out ok. Raising the low voltage setpoint up from 180V does not appear possible with AS4777 country code selected.

To try and replicate the error, we have disconnected each phase one by one however the system works correctly under phase failure conditions. The next thing we are planning to try is to simulate the grid voltage dipping by installing an autotransformer on one incoming phase and ramping the voltage down to around 200V whilst under load (similar load as the time of the shutdown).

If you have found a solution to your issue would you mind letting me know as this will save us from further investigation. Thank you.

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warwick avatar image
warwick answered ·

I experienced this at a site and upgraded to 469 and there have been no further occurrences.

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Thanks will upgrade we are on 465 and let you know.

@Wehrner@onesolar.co.za did the firmware upgrade make any different. Probably 469-471 is latest now depending on kit.

Thanks for following up. We have upgrade this morning and had power outage 18.00 this evening. The system did not go into overload anymore. It however showed a quattro low battery alarm and change the battery voltage to 41 V for 30 s. The system switched off and back on again.

That sounds like BMS freakiness.

nigelfxs avatar image
nigelfxs answered ·

I am running a "Multiplus-II 48/3000/35-32", in a single-phase installation, and also experienced the same "Inverter Overload" alarm just as the grid failed.

Additional info:

  • Firmware version = 465.
  • AC loads = 550W.
  • Solar power available = 1500W.
  • The LiFePO4 battery was over 53V (60% SOC).

The inverter has been running fine for over 14 months - this fault occurred for the first time a few weeks ago, but has not re-occurred.

I am not sure if it is relevant, but the VRM Logs show the mains voltage collapsed and briefly returned before turning off completely. See image below.


1582546465707.png (50.5 KiB)
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nigelfxs avatar image nigelfxs Daniël Boekel (Victron Energy Staff) ♦♦ ·

Hi Daniel

The Country/Grid code Standard is set to South Africa and the LOM Detection is set to "Type B (Grid Code Compliant)".

I have not tried adjusting the ac disconnect voltage, since this has only happened once even though we have had many power cuts in the last few months. I will rather monitor this and report back if it happens again.

Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Wehrner@onesolar.co.za

This probably has to do with the way the voltage drops on the grid, there's a good explanation here:

https://www.victronenergy.com/live/multiplus_faq#minimum_voltage_levels

about how to set the AC input disconnect voltage higher, so the system will not try to follow the grid down to the standard value of 180V


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Thanks for the feedback Daniel. We have change the voltage settings to the following. We have just had another loadshedding. Not the system switched off stating low battery even though the voltage and state of charge is above 90%. The settings per below.


The error message :


VE.Bus System Automatic monitoring Low battery: Alarm 2020-03-09 10:05:41 31s

VE.Bus System Automatic monitoring Low battery: Alarm 2020-02-21 12:02:27 31s

System overview Automatic monitoring Grid status: Grid lost 2020-02-21 11:34:21 8s





1583743339532.png (35.5 KiB)

Hi Daniel. Don't you think the issue is related to the LOM functionality.

When connected to a generator, or to a grid with a long extension cable or long ‘last mile’ cable, the pushing and pulling on the grid does create high currents, and as a result the inverter/charger algorithm can become unstable and switch itself off in overload.


wehrner avatar image wehrner Daniël Boekel (Victron Energy Staff) ♦♦ ·

Thanks

64cfd949831d

Or

7c386653a352


Hi Daniel. How can we escalate this through the correct channels. we are getting a lot of heat on these issues at the moment. they are pretty serious klients pay big dollars for the system to work when there is power outages and then it fails

Hi @Wehrner@onesolar.co.za

Are you an installer? in that case you go to your distributor, he / she is your first line of support, and when he/she doesn't know the answer, goes to Victron sales agent of that region.

All this is well known by any trained Victron installer.



petajoule avatar image
petajoule answered ·

Does just one of the Multis go to overload, all of them, if it happens is it random which one or always the same?

Seems to be a 48V system. Which multis are that? What is the battery capacity? Firmware?

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