Analytics methods¶
In addition to the physics models of the Digital twin, Tipspeed derives a set of diagnostics from operational data and satellite imagery. These diagnostics aim to quantify the production lost and its causes, and provide a list of prioritised corrective actions.
Nacelle direction offsets to North¶
The nacelle north offset is the error between the nacelle direction a turbine reports in SCADA and its true direction relative to geographic North. Tipspeed measures it from high-resolution satellite images, with a patent-pending method. See Nacelle direction offsets to North.
Yaw misalignment estimation¶
Yaw misalignment is the angle between the direction a wind turbine's rotor faces and the wind direction. Tipspeed estimates it for every turbine without additional sensors, by combining high-resolution satellite imagery with a numerical weather model. Across 23 blind tests against nacelle-mounted lidar, the mean absolute error was 2.25°. See Yaw misalignment estimation.
Optimal yaw offset¶
The optimal yaw offset is the yaw misalignment that maximises the power output of a turbine. It is the target of a yaw recalibration, rather than zero. Tipspeed estimates it for each turbine from SCADA data only. See Optimal yaw offset.
Expected power and lost production¶
Expected power is the power a turbine would have produced in each 10-minute period, including periods in which it was stopped, derated or had missing data. Lost production is the difference between expected power and the power actually produced. Each loss is attributed to the operating status of the turbine, following the production-based method of IEC 61400-26-1. See Expected power and lost production.
What a timestamp means¶
The meaning of a time value depends on the type of record it labels: a 10-minute record is labelled by the end of
its interval, an aggregated period by its start.
See What a timestamp means.
Wake gain from stopped turbines¶
A stopped turbine produces no wake, so the turbines downstream of it produce more than they would if it were running. This gain is reported as a separate step of the energy chain. See Wake gain from stopped turbines.
Operational power curve estimation¶
The operational power curve is the power curve that a turbine achieves on its site. Tipspeed estimates it by calibrating the wind speed input of the digital twin until the simulated power matches the SCADA power. See Operational power curve estimation.
Upgrade analysis¶
Upgrade analysis measures the production gain of a turbine upgrade by comparing a test group with a control group over the same months. Each group is first compared with its own expected production, so the effect of wind conditions cancels out in the difference. See Upgrade analysis.
Controls operation¶
The Controls operation view compares how the pitch, rotor speed and yaw controllers of the turbines operate. Each turbine is compared with the other turbines of the farm, and month by month. See Controls operation.