question

denzel avatar image
denzel asked

Grid Loss even thou the grid is available (Multiplus(s) in parallel)

Good Day,

I have an issue with my setup going into inverting mode even thou the grid is available , i also noticed that even if the is no ac loads the vrm reads a value between 30W and 40W, using ve config the units have no errors:


My setup overview :

3 Multiplus in parallel

FW version : 497

1 250/100 MPPT

6 Victron 220ah gel batteries .

GX Color control .

Im using an assistant HUB-1 keep batteries charged feed surplus back to grid.

@Guy Stewart (Victron Community Manager) please can you advise.

state.pngfw.pnggrid.pngac-loads.png


Regards

gridmultiplus in parallel
grid.png (20.1 KiB)
state.png (24.0 KiB)
fw.png (18.1 KiB)
ac-loads.png (55.1 KiB)
5 comments
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Alexandra avatar image Alexandra ♦ commented ·

@Denzel

Your system itself will be consuming power hnece the 40W. (The three inverters themselves and any other components needed to run them).

Grid rejection may be the cause of no grid conditions. You will need to investigate what is out of the grid code parameters you have set. If it is all in parameters it will possibly be resistance in the connection to the grid.

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denzel avatar image denzel Alexandra ♦ commented ·
Hi Alexandra ,


Thanks for your reply. I concur with the consuming power. However the grid issue is baffling as i had a mutlimeter on the AC input side of the inverters and at the time vrm read grid loss alarm the AC input side read 230V .

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Alexandra avatar image Alexandra ♦ denzel commented ·

Then it is resistance to grid possibly more a rejection based on that.

Sometimes odd stuff like neutral earths. Wiring too big is another one.

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denzel avatar image denzel Alexandra ♦ commented ·
I will check the grid settings via ve config. The wiring is is as per spec and almost very similar in lengths.


will update the post.

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Alexandra avatar image Alexandra ♦ denzel commented ·

It may not necessarily be the set up. I mean the resistance in the lines to grid. And as nickb mentioned can factor in with the rejection.

I had an experience at home with the grid, victron was happy, a tree fell on the lines. After the repair (the usual twist back together) the victron rejected the grid more often.

I have also seen where more foliage from trees touch the lines, more grid rejection.

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3 Answers
nickdb avatar image
nickdb answered ·

It is behaviour I see regularly here when the grid is under strain, voltage within the limits but the system starts inverting. When the grid stabilises everything returns to normal.

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denzel avatar image denzel commented ·

Hi nickdb- there is no patten as it only happed 5 times , 2 on Friday load at +-600W lasted 7mins and 15mins


Early hours of this morning load at +-725W lasted 7s / 18min and 30mins +- .


the intervals between outages were about 30mins at max.

Yes when the grid "returns" everything acts normal .

Regards

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nickdb avatar image nickdb ♦ denzel commented ·
Just to clarify, this isn't about the load. You may well have an unstable grid at those moments, as happens here in SA with some regularity.



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denzel avatar image denzel nickdb ♦ commented ·

certainly not load - i suspect it maybe grid related however at the time of testing maybe the grid was live but could have issues..... i will check the if there is power between N and E today as that maybe an issue too...

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denzel avatar image
denzel answered ·

Update: I have checked the N - E voltage and they with in 1.9V . This morning again around the same time with no loads the system had a grid loss alarm again. 3 times. I now changed from "HUB-1" to an ESS mode to determine if this is related to a config issue.

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denzel avatar image
denzel answered ·

Hi Guys,

I found the issue relating to my grid loss problem. The was not on the Grid side but a setting on the Master Victron unit . The AC High Disconnect Voltage was set to 240V and my grid at time suppled 242V which then the Multiplus disconnected the AC until the Grid went down to 235V .


Had the Victron alarm alert reported something like "AC Input Volt High" instead in "Grid Loss" we would have found the issue much faster.

Still a very good feature to have .

"The setting is found under the Grid tab in VE Config"

@nickdb @Alexandra thank you very much for your assistants in this matter.

Regards


Denzel

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Alexandra avatar image Alexandra ♦ commented ·
@Denzel

Thanks for the feedback. Appreciated.

There is one alarm there for that. The high voltage alarm has to be set as a specific VRM warning, I have them on a few systems here.

Grid lost is just a general one set on the GX.

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