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Table of Contents

Turbine Faults

Use the Specify > Control Systems > Turbine Faults window to specify pitch fault cases, generator or network fault cases, yaw fault cases and "other" faults.

Pitch faults

Enter the following data to specify pitch faults (applies also to ailerons or airbrakes if defined):

  • Pitch failure mode: for each blade, specify the type of failure for the pitch mechanism.

  • None: The pitch mechanism is operating normally.

  • Permanently Stuck at the Pitch of failed blade.

  • Constant rate runaway at the Constant rate demand.

  • Free or Constrained by a constant torque and/or the pitch bearing friction.

  • Seizure at a given time or when passing through a given angle after a given time.

  • Recoverable: Specify whether the pitch failure is recoverable. This means that the safety system pitch action will override the pitch fault.

  • Pitch of failed blade: For each blade where the pitch mechanism is Permanently Stuck, specify the angle at which the pitch is stuck.

  • Time for pitch failure: Enter the time at which the failure will occur.

  • Constant torque demand for Free/Constrained failures.

  • Fail when passing through: Angle at which seizure will take place after the Time for pitch failure has passed.

Generator and Network Faults

Four types of generator or network faults can be modelled:

  • Grid loss: Specify the time from the start of the simulation for the grid loss to occur.

  • Generator short circuit: Enter the time from the start of the simulation for the short circuit fault. Different short circuit models are available for synchronous generators as long as a transient model is selected: select the type of fault required. In other cases, a file containing a time history of generator torque during the fault can be provided. Enter the path to the short circuit file. The file should be in ASCII format, and the first line should be an integer specifying the number of points in the time history. The remainder of the file can contain either 2 or 3 columns. Column 1 is the time in seconds from the start of the fault. If the file contains only 2 columns, the second column is the generator torque (Nm). If the file contains 3 columns the second column is the maximum generator torque and the third column is the minimum generator torque (both in Nm). The power production control is allowed to continue to specify a demanded generator torque between these two values.

  • Network voltage disturbance: If a user-defined generator model has been specified, a network voltage disturbance factor input will be provided to the generator model. Network voltage disturbances are not used if a generator model has been specified. To define a network voltage disturbance, enter the time for the start of the voltage disturbance, and select either External Input File or a user defined Lookup table. The external input file should be an ASCII file containing an integer specifying the number of points on the first line, and then two columns on the subsequent lines giving time in seconds since the start of the disturbance, and the corresponding voltage disturbance factor. The voltage disturbance factor is expressed as a fraction of the nominal network voltage.

  • Network frequency disturbance: If a user-defined generator model has been specified, a network frequency disturbance factor input will be provided to the generator model. Network frequency disturbances are not used if a generator model has been specified. To define a network frequency disturbance, enter the time for the start of the frequency disturbance, and select either External Input File or a user defined Lookup table. The external input file should be an ASCII file containing an integer specifying the number of points on the first line, and then two columns on the subsequent lines giving time in seconds since the start of the disturbance, and the corresponding frequency disturbance factor. The frequency disturbance factor is expressed as a fraction of the nominal network frequency.

Yaw faults

If a yaw system is defined, three types of yaw fault can be specified:

  • Constant rate: Enter the constant rate for a yaw runaway, and the position of any end stop if required. The end stop is defined clockwise from north.

  • Constant torque: Enter the constant yaw failure torque.

  • Free/Constrained: Enter any linear stiffness, linear damping and yaw friction which are active during the yaw failure.

Other Faults

An external controller fault can be specified in the Other faults tab. This allows the user to define an integer number which is passed through in swap array number 161 at the specified time. This is equivalent to the GetControllerFailureFlag in the controller API. The user can then design the user-defined controller to interpret this input number and take the appropriate action.

Last updated 14-11-2024