Hello everyone!
I am in the middle of my first attempt at troubleshooting what I assume to be some sort of system error that occurred between our Fronius Symo bank and Victron Quattro bank during a grid low voltage event. I got as far as downloading the raw data from the VRM and highlighting the significant events/timestamps, but I’m not familiar enough with the equipment to be able to figure out what might have occurred. I’m also still new to the Victron community, so please feel free to educate me if I should be first reaching out to Fronius, a distributor, etc.
A bit about the setup: The system is a grid-tied ESS with a PV array and a bank of 45 48V 100Ah batteries. It is installed in a hospital in rural Malawi (southern Africa). We have a bank of six Victron Quattro 48/15,000/200, configured to 3-phase. To these we have seven Fronius Symo 15.0-3-M connected, one (“Fronius 1”) to the AC Input 1 of the Quattro bank, and the other six (“Fronius 2-7”) to the AC Output 1. The grid is 3-Phase 230V 50Hz. On the front end we have a Carlo Gavazzi Smart Grid Meter (to prevent feed-in) and a Ziehl grid monitor (which can automatically disconnect the system from the grid via a Schneider contactor in the event of unstable or dangerous voltage/frequency in order to help protect the equipment), both on the line-side of the manual disconnect switch.
The issue in question happened about two weeks ago, during a period of low grid voltage. After the Ziehl monitor and/or the internal Quattro monitors disconnected and reconnected the system several times due to low voltage, the Quattros disconnected the system yet one more time, but this time the Fronius Symos tied to the AC Output went from “Running (Throttled)” to alternating between “Error” and “Startup 3”. They had previously been continuing to operate and supply power during all the previous disconnections. We noticed the loss in solar power via the VRM and attempted to solve the issue by manually switching off the main switch incoming from the grid. At this point the Symos booted right up and started producing power again. About an hour and a half later we tried flipping the main switch back on and everything was fine. (Looking closer at the voltage readings, I suspect that we could have just toggled it off and on and it would have been fine in the moment too.) One other curious bit is that earlier in the morning the cutoff voltage seemed to be 210V, but the last time the Quattro bank disconnected the input the voltage remained at around 215V. In spite of this, the Quattros never again reconnected the input.
This is a link to the raw data I’ve been analyzing. I hid what I thought seemed to be irrelevant columns and highlighted the eventful times (annotated on the second tab).
This has not been the first time that this type of issue has occurred. However, this was the first time I was able to “catch it in the act” and find good data to parse. Given the number of grid disruptions we experience - and the long duration of some of them - it is extremely concerning to unexpectedly lose the ability to utilize solar energy and apparently also the ability to automatically reconnect to the grid, without need for manual intervention.
Has anyone else experienced an issue like this? Or does anyone know what might be the root issue?
Thank you in advance for your help!