My system utilizes six 48V 10000 Quattro units to form a 3-phase 60kW system. Three 20kW Solis grid-tied inverters are connected to the AC Out terminals, and the battery bank consists of sixty Plontech UP5000 batteries. A 50kVA diesel generator controlled by a DSE8610-MKII is connected to the AC In1 terminal. My question is: How should I configure the system to ensure that when the Solis grid-tied inverters and the diesel generator are charging the batteries simultaneously, the current from the grid-tied inverters does not flow back to the diesel generator?
Wow, big system.
Please lets have some images of this set up.
Who installed it, as surly they thought about the issue you ask about.
Are you using ESS? Does the back feed only happen when the grid is off?
Would a blocking diode work just after the generator? (since the grid is most likely off, the extra power has to go somewhere presumably the batteries).
Or you could limit the charge current coming from the generator and the PV inverters?
Just some ideas.
Are you of grid? Or is there a grid supply next to the generator?
You really have to be careful with this high energy system! The charging from generator and Solis goes over the same charger. The Victron system has NO way of controlling either of the sources output power. The Solis will always have a higher voltage than the genset because it thinks that’s the grid. And with the slightly higher capacity it will overpower the generator.
Do the Solis inverters that you are using have inputs for remote control or demand management?
If so, the simple case and least likely to fail is to just shut down the Solis inverters entirely if the generator is operating. You can do this by using a Programmable Relay Assistant in the Quattro config to turn on a relay if AC Input 1 is active (that relay contacts are used to kill the PV inverters via the remote shutdown). This is the most reliable way to do it.
If you feel that you must run both generator and Solis inverters simultaneously, a more complicated solution could be to monitor the AC loads and the Charge Current Limit (CCL) and State of Charge (SoC) for the Pylontech batteries, and when you get to a point where it is more likely you will be back-feeding power to the generator (ie: total power consumption (AC Loads+Battery charging) < Solis+Generator), you can disable the Solis inverters or force the Quattros to ignore their AC Inputs. This is a pretty dynamic situation (AC loads could disappear quickly, leading to a surplus of power from the Solis inverters with nowhere to go). I’d definitely leave some margin for quick load changes. Or maybe use the energy meter on the Solis (which you must have) and wait for it to approach going negative (probably too late - not ideal 
)… none of this is simple.