Navigation:  Project design > Grid-connected system definition > Grid power limitation

A limit to the injected power is sometimes required by the grid manager.

For maximizing the annual yield, people often install an over-sized PV system, and accept some energy loss during peak-shaving.

This limit may be defined in the calculation version dialog, button "Energy Management".

Here you can decide whether you have a grid limitation, and specify its value.

The limitation may be defined:

- either at the inverter level:  the inverter power is limited to the rated value, and the power injected into the grid is further reduced by the losses defined after the inverter  (auxiliaries, AC wiring, transformer).    

- or at the injection point level: the maximum power delivered to the grid is indeed the rated limit, the inverter will have to deliver a higher power for compensating the losses after the inverter.  

This limitation may be required:

- either as active power  (expressed in kW),  

- or as apparent power [kVA]: in this case the effective active power [kW]  is limited at a lower value than the apparent power limit [kVA]. The Cos(Phi) may be specified in monthly values.

The limitation itself will always be managed by the inverter as a clipping. By default, it will be accounted for in the simulation results as an inverter overload loss. You can change this behavior by checking the box "Account as separate loss". In this case, the part of the inverter clipping that comes from the injection limitation, will appear as a separate loss, right before the grid injection. The inverter overload losses will not contain this contribution any more, and the power at the inverter output will be increased by this amount. This does not correspond exactly to the physical behavior of the system, which will always clip at the inverter, but it is meant to show explicitly the part of the clipping losses due to the injection limitation.