External contactor/ transfer switch for large quattro /generator system

Q&A and troubleshooting
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1

Hi all.

I have adopted a large 3 phase system consisting of 4x parallel quattro 15k per phase with a 300kva generator.

When i arrived to site, there were 2 quattros with burnt out input relays.
I replaced the ac input boards and tested the system, All seemed ok.

After few weeks, input relays cooked again.
The ac input current limit was set for 180A from memory, so one would assume 45A to each quattro, well within the relays 100A current rating.
Ac cabling was checked for equal lengths on the parallel connected units.

I replaced the relays again and have limited the input current to 95A to prevent burning relays again.
I have spoken to a few techs and came to the conclusion that the relays aren’t closing at precisely the same time and thus the first relay to close is taking the full generator current.

I have read the article that the multiplus units have a special .s99 firmware which allows for an external transfer switch.
This would mitigate the burning input relay issue, but alas is not available for the quattro series.

My question is, is there a way to have an external contactor/ transfer switch for this quattro system?
If so, how would it be implemented.

2

Just an addition to this post.

I have submitted a support request with Victron professional on the 10th june which was forwarded to the company who sold the quattros to the original installers.
It has been nearly a month and still no response from Baywa.re.

Not happy with the support or lack there of from them.
Not to mention the client is disappointed with the lack of support.

3

If that was the cause of the relays burning out, then enabling Dynamic current limit would solve the issue.