Inverter saturation, commonly referred to as “clipping”, occurs when the DC power from the PV array exceeds the maximum input level for the inverter.  In response to this condition, the inverter typically adjusts DC voltage to reduce the DC power.  This is done by increasing voltage above the MPP voltage, thus reducing DC current.  Most, but not all inverters self-limit.

In addition, some inverters self-limit in response to high temperatures inside the inverter cabinet.  Such behavior protects the internal components (e.g., capacitors) from accelerated damage.  Elevated temperatures can arise when active cooling fails (e.g., fan malfunction, filter clogged), or as a result of high ambient temperatures and installation problems (e.g., South-facing install).

While most inverters can handle overloading the power (DC Rating of Array at STC/AC Capacity of Inverter > 1), there are important limits to how this can be done.  For example, the DC voltage of the array must not exceed the maximum input voltage of the inverter.  In addition, the maximum short circuit current of the array must not exceed the maximum short circuit current of the inverter.