System availability

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Basic info

Description

System availability is the percentage of a system that is available over a period of time. It is an indicator of how quickly faults are identified and remedied.

Prerequisites

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
Default threshold value greater than 100W/m²

Further details

Standard formula and calculation

Within the measurement interval, the entire plant is either available (100%) or not available (0%). If the energy is not equal to 0 within an interval, the availability is 100%.
System availability is only calculated during intervals where irradiance is greater than 100 W/m².
Intervals in which energy data is missing are treated as if the system is available.
The system availability calculation is not available for the current day.

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

Sample calculation

Interval	Irradiance (W/m²)	Energy (kWh)	Result
I1	90	10	Not rated
I2	125	20	100%
I3	200	30	100%
I4	80	0	Not rated
I5	250	0	0%
I6	200	NULL*	100%
I7	150	30	100%
I8	130	20	100%
I9	110	0	0%
System availability			5/(5+2) = 71.4%
*NULL means no data available for this interval

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Basic info

Sample calculation

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