Wind power generator
In this section the wind power generator is described and its associated calculations.
General information
The object Generator, wind power is used to be able to perform wind power specific calculation using the add on module for wind power. Without the module the object behaves as a normal generator.
The wind power generator is mainly based on the normal generator object. The production for a wind power generator can be regulated by wind series, and calculations for flicker can be performed, based on AMP.
Attribute form
In the Generator data tab values are entered as for the normal generator. In the Windpower tab values specific for wind power generator are entered.
It specifies the type of generator connection that is used, doubly fed induction generator (DFIG), directly connected or full power converter. Maximum active and reactive power refers the power the power plant does not exceed, regardless weather condition (measured as a ten second mean value).
For calculation of the flicker emission N120 is specified, which relates to the maximum number of allowed connection during a two-hour interval, as well as the turbine used. The code list for the turbine stores flicker constant, flicker step factor and the voltage change factor for the turbine. All constants are specified for four different short circuit angles, and the one that most closely match that of short circuit angle in the current delivery point will be used in the calculations.
(The other fields in the tab are used for load profile calculations (hour series calculation)).
Flicker values
For flicker calculation N120 is specified (maximum number of starts during a two-hour interval),
and turbine type, which indicates the values specific to the turbine type. These values consist of:
-Cf - flicker coefficient
-Kf - flicker step factor
-Ku – voltage change factor
All stated for short circuit angles 30°, 50°, 70° och 85°.
If no value are stated, then the extreme values ku=3 and cf=20 will be used for calculations.
Calculated values
The wind power production distribution need to be greater than 0% to consider wind turbines in the calculation when starting the network calculation.
Calculation procedures for distributed generation provides in addition to all the standard results, the following:
- Change in voltage at the connection at the current delivery point
- Flicker during operation
- Flicker at startup
- Voltage change at startup progress
- The required short-circuit power not to exceed set limits for flicker
Calculations
The flicker calculations are based on the report AMP.
For wind turbines, the maximum active and reactive power are used for calculations if specified. For direct-connected generators the maximum reactive power is estimated according to the following equation if not specified manually:
Flicker during operation is calculated using the following equation:
Flicker at startup is calculated using the following equation:
Voltage change by the startup process of a wind turbine is calculated using the following equation:
Voltage change when switching is calculated using the following equation:
