The objective is to define an inverter maximum power (Pnom eff) which should correspond to the Grid specified limit power (PNom grid), plus the AC losses after the inverter (wiring, transfos, auxiliaries, etc).
Can maximum inverter power limit grid feed-in?
The values of „maximum inverter power“ have always positive sign. Therefore they only limit the charging values for grid setpoint. They cannot limit the negative values for grid feed in. Using Grid feed-in → Limit system feed-in instead, also cannot solve this problem.
Grid-connected PV inverters have traditionally been thought as active power sources with an emphasis on maximizing power extraction from the PV modules. While maximizing power transfer remains a top priority, utility grid stability is now widely acknowledged to benefit from several auxiliary services that grid-connected PV inverters may offer.
How to set grid connection with limited power?
You are advised to choose Settings > Grid connection with limited power and enable the grid connection with limited power function. To enable this function, you need to set power meter, inverter, and grid connection with limited power parameters. This section describes how to set grid connection with limited power parameters.
Grid Connection Some properties of a PV inverter grid connection can cause the grid voltage at the inverter to increase and exceed the permissible operating range if the feed power is high. If this occurs, SMA grid guard, an independent disconnection device integrated into the inverter, will safely disconnect the inverter from the grid.
If „maximum inverter power“ goes back to a higher value, the grid feed in also goes back if grid setpoint is that high. Nevertheless, I expect same behaviour for the “Limit system feed in”. This would allow high inverter power, high self consumption but only low grid feed in.
o The nominal power of each MPPT, taking temperature and Power factor into account o The possible power sharing predefined between MPPT inputs of inverters, o The different charges of each MPPT input (some with N and some with N+1 strings), o The possible self-consumption or battery charging for this hour should be added to the grid limit,