BERTA Operation of BERTA On-Site Tests

Once all the preliminary calibration, setting and signal selection steps are complete, you can proceed to the test mode. The following operations are provided:g:

GO Acquis	Starts signal acquisition and recording.
GO Disturbance	Starts disturbance.
Reset dFreq Sim.	Resets simulated frequency error signal to zero.
Mean P S values	Calculates the new mean value values for power and main servomotor position
Mean Speed value	Calculates the new mean rotation speed value
Operating mode	Lets you select the operating mode: islanded system (closed-loop) or open loop. The disturbance types available depend on the operating mode selected.
Islanded grid (closed-loop) disturbance	Step Step processed by a 2nd order filter Fixed frequency sinus Pulse Ramp Triggering of selected units
Open loop disturbance	Step Step processed by a 2nd order filter Fixed frequency sinus Pulse Ramp Frequency sweep (0.01 to 5 Hz) - Pulse train (0.01 to 5 Hz)

Note: Before each test, we recommend saving the new initial conditions for power and main servomotor position by clicking on the GO Mean PS button. This operation must be executed only when the BERTA speed governor switch is OFF and when there are no disturbances.

Each time an acquisition is launched using the GO Acquis button, the recording starts. Pressing on this button during the acquisition stops the latter and the recording is closed. A 10-second delay to close the file is required before starting a new acquisition. After this delay, the recording file increments by 1 and a new acquisition can be launched.

Each time a recording file is closed, the file is automatically transferred from the workstation to the laptop computer (directory: “…\BERTA_training_3_0_SM_Comm\OpNTOtarget”). These are MATLAB files identified as “essai_NO.mat” where “NO” represents the test number incremented by 1 for each acquisition launched. The change date assigned to each file is the file transfer date and not the test date. Therefore, we strongly recommend writing down the exact time a new acquisition is launched to allow accurate tracking of the tests.

The test procedures are described in the following sections based on the type of disturbance.