Quattros leak current to ground when in bulk mode

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paul-berberian asked Oct 24, '22

Quattros leak current to ground when in bulk mode

We have two 8K Quattros in parallel (master slave) connected with a 100A autotransformer. We notice that when the inverters are in charge "Bulk" mode or very heavy load we measure current on the ground coming off the AT. We have enabled the ground relay within the AT / Quattro setup and connected the wire from the Quattro master to the AT. Thoughts on what is causing the leak while the Quattros are in charge mode? It happens with shore power or gen.

@Daniël Boekel (Victron Energy Staff) any thoughts

Autotransformer Readings Under Certain Conditions



Amps	IN			OUT
Conditions	Black	Red	Green	Black	Red	Green	White
Shore Power Connected - Under Load ~40A	39.36	29.73	1.19	36.20	32.59	0.77	7.24

No load 120V and 240V off - shore power ON - inverter charger bulk	6.01	5.69	1.05	0.00	0.05	0.80	11.81
No load 120V and 240V off - shore power OFF - inverter charger on but no AC	0.00	0.00	0.00	0.00	0.00	0.00	0.00
No load 120V and 240V off - generator ON - inverter charger bulk	9.68	9.20	1.74	0.00	0.19	1.45	19.29

MultiPlus Quattro Inverter Charger Grounding

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Modifications Space

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Answer 1 · 2022-10-27T16:09:23Z

paul-berberian answered · Oct 27, 2022 at 04:09 PM

@Mike Dorsett Any ideas since you were so helpful on my last question. The leak only happens when the Quattros go into Bulk charge mode - Absorption and passthrough there is no leak. We've double checked all the wires and are awaiting Victron feedback. Thx

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Trevor Bird commented · Oct 27, 2022 at 08:11 PM

I can’t imagine two Quattros in series connected by an autotransformer so it is a bit hard to comment. Perhaps a circuit diagram would be helpful to indicate how it is setup.

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paul-berberian Trevor Bird commented · Oct 28, 2022 at 12:09 PM

I meant parallel - sorry.

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quattro-high-level-drawing-1.jpg (153.3 KiB)

Answer 2 · 2022-10-29T20:03:26Z

Mike Dorsett answered · Oct 29, 2022 at 08:03 PM

@paul-berberian

From your above current measurements, it looks like you have some major issues.

1) In the first set, there is nearly 10A difference between the current measured on the black and red wires - assuming these are the live and neutral into the Quatro at 240V, this leads to 1 of 2 conclusions - there is a major power leak to ground, and not all of the ground current is being measured on the green wire, or the current measuring device or method is inaccurate.

A diagram showing current measuring points and layout of system is needed.

Under steady load conditions, current measured on the black and red wires should be identical to 0.5%+/-1 count.

Ground currents should be <<0.1A.

Other points to check: position, continuity and currents in neutral / ground bonding wires & currents in grounding cables to all parts of the system. Elimination of ground and Neutral loops.

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