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The following parameters are often specified by inverter's manufacturers   (see Grid inverter, Main parameters):

- Nominal PV power of the array. It may be understood as the recommended nominal STC power of the PV array.

- Maximum PV power is the recommended absolute maximal STC power of the PV array.

- Maximum PV current is the absolute maximal current admissible at the input of the inverter, usually the ISC current of the PV array at STC.

These values are sometimes presented as limit requirements, which may act on the warranty.

Nevertheless we consider that these requirements don't have a real physical meaning, as they depend namely on the plane orientation  (please see the sizing tool). For example in a façade system you can put a Pnom ratio (Array / Inverter) of a factor of 2.

If the inverter device is correctly designed, these limits normally don't present any danger for the device when running in overload. The inverter simply will adjust the power drawn from the PV array by displacing the operating point along the I/V curve, so that there is no additional power dissipation, and therefore no accelerated ageing.

The inverter provider will in most cases propose over-sized inverters, arguing that if there is a power peak it could be lost. This is a specious argument, as dispatched in short periods this represents a very low amount of energy. The cost of the over-sized inverter is to put in balance with this very little loss.

If the inverter's provider sets these limits as contractual (i.e. acting on the warranty), you should check these checkboxes. In this case the sizing tool will consider these as absolute limits, give warnings in red and prevent the simulation.

Otherwise this may produce an info message when defining the sub-array (in blue), that you can ignore.