Availability

Availability calculations are made on definitions that are generic, transparent, unambiguous and based on realistic measurements. All turbine time is recorded and assigned to fifteen mutually exclusive categories as shown in the table below. The availability may be calculated over any time period.

Default calculations are supplied with the system. In addition the user may define their own availability calculations based on the addition and division of these time categories.

Availability category	Time	Status
No SCADA	T1	The SCADA system is out of operation.
Force majeure	T2	Force Majeure condition exists on the wind farm.
No comms	T3	The SCADA communications system is functioning correctly but no data communication is available from the turbine controller.
On line	T4	Turbine generator on line.
Grid limits stop	T5	The grid is outside agreed operational limits.
Ambient temperature stop	T6	The wind farm ambient temperature is outside the agreed turbine operational limits.
Off line wind in limits	T7	Turbine is released to run and wind is within limits but turbine generator is off line. This may be due to turbine operations such as cable unwinds and generator changes.
Off line wind out limits	T8	Turbine is released to run but generator is off line due to wind conditions being outside the operational limits.
Fault stop wind in limits	T9	Turbine is stopped with a turbine fault requiring operator intervention. Wind is within operational limits.
Fault stop wind out limits	T10	Turbine is stopped with a turbine fault requiring operator intervention. Wind is outside operational limits.
Maintenance stop wind out limits	T12	Turbine is stopped for scheduled or unscheduled maintenance while the wind is outside operational limits.
Operator stop wind in limits	T13	Turbine is stopped by operator command while the wind is within operational limits.
Operator stop wind out limits	T14	Turbine is stopped by operator command while the wind is outside operational limits.
Constraint stop	T15	Turbine is stopped for operational constraints (time of day, noise etc). May be manual or pre-programmed.