Performance ratio (PR)

The performance ratio is calculated based on the system yield, installed DC power, and irradiation at the module plane. It indicates how well the PV system can convert solar energy. Typically, an annual PR value of 75-85% is considered good.

• Energy sum at system level defined as the term E_Z_EVU

• Irradiance data from a sensor defined as the term G_M0 or satellite data

Standard formula and calculation

• By default, the formula from IEC 61724-1 is used in VCOM.

• The smallest period of the performance ratio calculation is one day.

• Monthly and annual values are aggregated accordingly and are weighted based on the projected energy.

If you wish to define the input parameters differently, see KPI editor for PR and system availability.

PR chart settings

Define green, yellow, and red thresholds specific to each system. These settings are reflected in the Performance ratio and Performance ratio comparison charts.