The objective of this experiment is to study the steady-state operation of the WTGS.
Real-time simulation results are shown in the “Main Interface”, “Secondary Interface”, and “Help Contents” tabs of the laboratory panel.

Part 1

Open the model with the default settings.
- Does the grid absorb or provide active power?
  Explain your observation.
  (Hint: see power flow results in “Help Contents” tab).
- Does the rotor absorb or provide active power?
- What is the rotational speed (in rpm) of the DFIG?
- Knowing that the DFIG nominal speed is 1500 rpm, what is the operation mode?
- Power flow 1: Save the power flow results via a screenshot, for example.
- Verify the power balance in terms of active and reactive powers of the system.
Increase the wind speed to 11 m/s.
- Does the grid absorb or provide active power?
  Explain your observation.
- Does the rotor absorb or provide active power?
- What is the operation mode of the DFIG?
- Power flow 2: Save the power flow results.
- Verify the power balance in terms of active and reactive powers of the system.
- Compare the results of Power flow 1 and 2.
  Explain any similarities or differences, if any.

Part 2

Keep the wind speed at 11 m/s, and change the reference reactive power to -200 kVAR.
- Does the measured reactive power follow the reference?
- How does the change in reference reactive power impact the rotor reactive power?
- Observe the waveforms in the “Secondary Interface” tab, what can you conclude in terms of the WTGS controllers?
- What is the voltage of the DC bus?
Decrease the wind speed to 9.15 m/s.
- Observe the plots of rotor currents in the Main Interface “tab”. Explain the non-sinusoidal current waveforms.
  (Hint: see power flow results in “Help Contents” tab).
- Does the decrease in wind speed impact the DC bus voltage? Explain.

Part 3

Change the wind speed from 9.15 m/s to 11 m/s.
Change the reactive power from -200 kVAr to 400 kVAR.
Switch from “Predefined” to “User” to have access to set your own reference speed.
Set the reference speed to 200 rpm and save the power flow results (Power flow 3).
Increase the reference speed to 210 rpm and save the power flow results (Power flow 4).
Compare the results of Power flows 2, 3, and 4. What are the disadvantages of imposing different rotating speed values than the optimal one?

Note

The optimal rotational speed is obtained when the switch is set as “Predefined’’.

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