Turbine-Main
The Main tab (figure 93) is first and consists of the following fields:
Figure 93: Turbine Types Dialog
Turbine name. This is how the turbine is referred to in the rest of the workbook and in the energy capture report. If you have several versions of the same turbine in your workbook, you should delineate them here. For example, you could use “Alstom ECO 100 3.0 Class 1A @100m” and “Alstom ECO 100 3.0 Class 1A @80m” to refer to two identical Alstom turbines at different hub heights.
Rotor Equivalent Wind Speed. This checkbox enables rotor equivalent wind speed for this turbine type. This still requires rotor equivalent wind speed to be enabled globally by going to Settings->Rotor Equivalent Wind speed. The idea behind this is that users are most likely only interested in rotor equivalent wind speed calculations for a subset of the turbine types within a workbook.
General. Use this section to house any notes on the turbine type. By default this section contains a disclaimer.
IEC Class. This refers to the IEC class of the turbine. This information is readily available as part of any turbine specification and is used to determine the site suitability (for use with suitability items).
The IEC 61400-1 edition under which the turbine was certified and from which the TI curves should be calculated in order to check compliance for effective TI. If “S” is selected under IEC Class, Custom Reference TI is added as an option to this dropdown list as well as a greyed out disabled button lower down. If Custom Reference TI is then selected, the button Custom Reference TI button becomes enabled.
Custom Reference TI – this button brings up a dialog which allows the user to specify a custom reference TI curve.
Rated Capacity. This is the rated or nameplate capacity of the turbine in kilowatts.
Peak output. This refers to the peak output of the turbine in kilowatts. This is generally the same as the rated or nameplate capacity.
Pitch/Stall Regulated. This is used to determine the form of the IEC air density adjustment.
Rotor diameter. This is the diameter of the swept area of the rotor disk or double the distance from the centre of the turbine noise cone to the tip of one blade.
Hub Height. This refers to the hub height of the turbine or the vertical distance from the ground to the centre of the nose cone of the turbine.
Cut-in Wind Speed. This refers to the wind speed at which the turbine starts spinning. The turbine may not be generating power at this wind speed but it may still generate a wake.
Cut-out Wind Speed. This is the wind speed at which the turbine shuts down. In reality, this tends to be a strategy rather than a single wind speed (see High-Wind Hysteresis). However, the current method for energy capture cannot take into account the second-by-second or minute-by-minute behaviour of the turbine. In the absence of such a method, the turbine is modelled as cutting out when the wind speed goes above the cut-out wind speed and cutting in again immediately when the wind speed goes below the cut-out wind speed.
Fixed/Variable Speed. This is used to calculate the loss due to the correlation of downtime with high wind events.
Number of Blades. This is self-explanatory.
Rotor is Tilted Back. This is the tilt of the turbine rotor in degrees from the vertical (or the tilt of the rotor axis in degrees from horizontal). Most modern turbines tend to be tilted slightly backwards. While the power curve takes this tilt into account, there is an effect on the energy losses due to inflow angles (see Section below on Losses).
Power Uncertainty – this is used in the uncertainty calculation, see Uncertainty
Figure 94: Custom Reference TI Curve
The Custom Reference TI Curve dialog can be edited directly or one can copy and paste from a spreadsheet. Openwind will stop reading at the first row that has zero or no wind speed value.