Hello Victron community
I have a question regarding Fronius inverters.
Our site is completely off grid, and our system comprises :
Pylontech battery modules (30xUS3000C)
Victron Quattro Inverter/ chargers (3X 15000VA)
DC coupled PV (20kW) - 4x Victron 250/100 MPPT's
AC coupled PV (10kW) - 2x Solar River inverters
AC coupled wind turbine (24kW) - 4x ABB Inverters
24kva Diesel generator
The Victron Quattros create a single phase Micro grid for the wind turbine inverters and the PV inverters, and we have various dump loads on site that are switched on based on battery SOC. The system works great when the dump loads are on or when the batteries are not fully charged. However, it is necessary to hold the batteries at 100% charge periodically to top balance the lithium cells and this is where the problem starts. We use frequency shifting to control the wind and PV inverters - if the batteries are full and we are not using all the power being generated, the Quattros shift to 53 Hz and the wind/ solar inverters disconnect. The Frequency then drops to 50Hz and they reconnect, and the cycle repeats. This means that the only way we can hold the batteries steady at 100% is with the MPPT's or with the diesel generator. I would like to add Fronius inverters to the wind turbine which would allow the Victron system to regulate the power from the wind turbine and allow the batteries to be held at 100%, similar to how a Fronius zero feed in PV system would work with Victron ESS.
The wind turbine has its own controller and can regulate its speed to 75rpm regardless of the load applied to it. The three phase comes from the alternator on the turbine into a wind interface box where it is rectified to DC (around 500v) at full speed. This DC is then shared between the 4x ABB wind inverters.
I would like to replace these ABB inverters with Fronius inverters.
I have attached a sketch of our system to help explain, and our system can be viewed on YouTube or on the Victron website as it is featured in their latest video.
Can anyone see any issues that might arise with this plan?
Any information would be greatly appreciated.
Many thanks
Jonathan
