This chapter explains the steps required to use the BERTA Certification application with the TestDrive software. The certification principles, the hardware components and the software used are described.

Certification Principles

BERTA Certification lets you check the technical characteristics of a speed governor in test conditions. You can test the control system or a programmable controller in the case of a digital speed governor. The controller generates signals for the servomotors based on set points or speed variations received from the AC generator.

The speed governor controls the following:

AC generator rotation speed.
Power operating point or at gate opening.

The programmable controller is designed to control these three operating modes:

Idle running at startup or stoppage.
Idle running in synchronous network.
Islanded grid running.

BERTA Certification can simulate these three operating modes.

For more details on how to start the application and use its interface, refer to the General Introduction chapter.

Certify_1 Button

The Certify_1 button provides access to four graphic display panels (one panel per dial) and two control panels (Indicators and Calibration).

Settings Panel

Click the Settings tab to set the following parameters:

AC generator simulation.
Conversion into volts of voltage signal generated by BERTA.
Conversion into volts of BERTA digital signals sent to speed governor.
Conversion into digital values of speed governor analog signals sent to BERTA.

Set all the parameters following the simulation requirements. These parameters can be saved to a file and automatically assigned at the start of the next simulation. See Stopping the simulation in the General Introduction chapter for instructions on how to save current simulation parameters or return to default settings.

Settings Panel

Graphic Panels

Graphics 1 to Graphics 4 tabs display the corresponding panels with graphs and have the same interactive menus. Only the signals displayed are different. Accordingly, only Graphics 1 panel will be shown.

Graphics 1 Panel

Range values and coordinate labels can be changed quickly to meet the simulation needs.

Graphics 1 Panel

V_FO	Speed (rated frequency 60Hz)
Vsim	Speed simulated by BERTA
Cd servo	Command servo (setting launched by the Certify_2 control panel)
DXref Berta	Servo motors’ reference position (user-defined parameters)
Out servo	Servo motors’ output signal

Graphics 2 Panel

Displays the same results as Graphics 1 panel, but with a larger scale.
Displays the output signal of resulting speed.

Graphics 3 Panel

Not used presently. User can display a signal of his choice here.

Graphics 4 Panel

D speed	turbine speed variations
Out servo	servomotors output signal
Pmec	turbine mechanical power
Pelec	AC generator electrical power

Dials Panel

Clicking the Dials tab displays the analog dials. Data shown in this panel are not recorded.

Dials Panel

Calibration Panel

Clicking the Calibration tab displays the analog input/output calibration panel. Make sure the AD and DA calibrations are set to the desired values. These values are factory-configured to compensate for minor errors in the analog/digital or digital/analog converters and do not require frequent adjustments.

Calibration Panel

Certify_2 Button

The Certify_2 button provides access to five control panels, four of which display functional diagrams for the models programmed in the test bench, with active buttons and switches.

Operation Control Desk

This panel is used to send commands to the training speed governor programmed by the BERTA test bench algorithm. All the buttons are available to change simulation commands and parameters.

Operation Control Desk Panel

This panel is only available if the Training selection is activated. It controls operations while in Training mode.
This panel lets you provide settings for the application’s internal speed governor.
It is possible to change the setpoint amplitudes. Hence, changes in the controlled speed, position or power will be made with a bigger or smaller disturbance, according to the selected amplitude.
There are three possible setpoint types: Step, Ramp or Sinus. Buttons on the left of each field are used to configure setpoint values.

Generic PID Speed Governor Panel

The figure below shows a generic PID type speed governor model. The diagram displayed contains buttons to change the generic PID speed governor parameters.

Note: This panel is only available if the controller is in Training mode.

The PID type switch lets you select the speed governor’s control mode:

Red	Only the speed error signal attacks the derived and proportional gains. The correction signal from the permanent droop only attacks the integral gain.
Green	The speed error signal and the correction signal from the permanent droop attack the three gains: proportional, integral and derived.

The load pick-up switch, in the lower right corner, lets you activate load pick-up acceleration:

Red	Load pick-up acceleration is inactive. Load pick-up, or the response to a change in operation set point, is slow.
Green	Load pick-up acceleration is active. The setpoint signal goes through an acceleration function that converts instantly the servomotors’ position control signal.

Speed governor gain and constant adjustments can be accessed directly using the buttons in the diagram.

Permanent droop (Bp) is added to activate the servomotors increase set point. This means that the operator changes the servomotors increase setpoint using the Hausse_servo button on the control panel and will then change the speed governor’s permanent droop value to activate the set point.
The selector offers three options:
- Type 1: Permanent droop in servomotors set point.
- Type 2: Permanent droop in servomotors stroke.
- Type 3: Permanent droop in power.

PID Speed Governor Panel

Classical Speed Governor

The figure below shows a classical speed governor model. The diagram displayed has buttons to change the classical speed governor parameters.

Note: This panel is only available if the controller is in Training mode.

The Bp type switch lets you select the origin of the permanent droop:

Red	Servomotors stroke. The setpoint is for an electrical opening.
Green	Power set point.

The Load pick-up switch lets you accelerate the load pick-up:

Red	Acceleration inactive. Load pick-up, or the response to a change in operating point set point, is slow.
Green	Load pick-up acceleration is activated. The setpoint signal goes through the acceleration function to converts instantly the servomotors position control signal.

Speed governor gain and constant adjustments can be accessed directly using the buttons in the diagram.

Classical Speed Governor Panel

Servomotors Panel

The speed governor hydraulic chain represents the main servomotors that open or close gates and the two amplification circuits comprised of the actuator and the distributor (Figure 61).

Note: The servomotors model is an important part of the Certification application because it functions in two modes: Training or Actual speed governor.

The hydraulic chain’s reaction lets you validate the functions of the programmable controller.

Three switches allow to adjust the operating modes of the hydraulic chain:

The Feedback Dist. switch lets you adjust the distributor feedback configuration according to the feedback signal from the programmable controller (green) or the application’s internal model’s gain output “Kf”.
The Feedback Servomotors switch lets you adjust the servomotor feedback configuration according to the feedback signal from the programmable controller (green) or directly from the application’s internal model.
The Table or Ksm switch that lets you select the mode representing the servomotors operating speed; either a function table or a fixed gain (Ksm).

Servomotors Panel

Gain and time constant adjustments are displayed at the bottom of the panel (Figure 61).

Gain in p.u. per volt and feedback signal offsets in volts from the real governor’s programmable controller are adjustable in the Feedback distributor and Servomotors feedback sections of the panel.

Hydraulic Turbine Panel

This panel lets you adjust the non-linear hydraulic turbine’s parameters.

Note: This panel also functions in two operating modes: Training and Actual Speed Governor.

Non-Linear Hydraulic Turbine Panel

Flow polynomial Q(X)	Q= C₂X²+C₁X¹+C₀X⁰. This polynomial represents the relationship between the flow and the servomotor stroke.
Flow variation polynomial dQ(w)	dQ= D₂ω²+D₁ω¹+D₀ω⁰. This polynomial represents the relationship between the flow variation and the turbine rotation speed.
Mechanical torque variation polynomial dT_mec(Q)	dTmec= E₂Q²+E₁Q¹+E₀Q⁰. This polynomial represents the relationship between the mechanical torque variation generated by the turbine and the flow, according to the mechanical torque equation given below.
Mechanical torque variation polynomial dT_mec(w)	dTmec= F₂ω²+F₁ω¹+F₀ω⁰. This polynomial represents the relationship between the mechanical torque variation and the rotation speed, according to the mechanical torque equation given below.
Mechanical torque variation polynomial dT_mec(Qw)	dTmec= G₂Q²ω²+G₁Q¹ω¹+G₀Q⁰ω⁰. This polynomial represents the relationship between the mechanical torque variation and the product of flow by speed, according to the mechanical torque equation given below. The equation for the mechanical torque is the following: Tmec = Tmx [ 1+ dTmec (Q) + dTmec (w) + dTmec(Qw)] where Tmx represents the mechanical torque depending on the servomotors opening and the net available head.

Certify_3 Button

The Certify_3 button provides access to two control panels and two graphic panels.

Command Desk to Actual Speed Governor Panel

This panel lets you transmit command signals to the actual speed governor. The panel reproduces roughly the actual operator console in a power plant.

The buttons in the two top rows are used to send commands from the operating mode to the actual speed governor. These settings are activated when the button is pressed and deactivated when the button is pressed a second time.

Command Desk to Actual Governor Panel

These command buttons will generate digital signals for the following outputs:

Reduced droop, = reduced droop
D-B On = dead band in service.
Manual = manual mode
Remote = remote mode,
Tension alt. = presence_V,
VAV return = vav_return.
Start •
Gate actuation = gate_act
Power actuation = ass_puiss,
Free = other_ass,
Pulse start = start_impuls,
Impulse stop = stop_impuls,
Speed up = h_vit,
Gate up = h_van,
Power up = h_puiss,
LOV up = h_lov,
LPUI up = h_lpui,
Speed down = b_vit,
Gate down = b_van,
Power down = b_puiss,
LOV down = b_lov, • LPUI down = b_lpui.

Digital Signals From Actual Speed Governor Panel

This panel corresponds to acquisitions from acq_3. It displays status detection signals from the actual speed governor.

Digital Signals from Actual Speed Governor

Graphic Panels

Graphics 1 and Graphics 2 tabs display the corresponding panels with graphs and have the same interactive menus. Only the signals displayed are different. Accordingly, only Graphics 1 panel will be shown.

Graphics 1 Panel

The top monitor displays:
- Pmec: Turbine mechanical power.
- Pelec: AC generator electrical power measured by the voltage sensor.
The lower monitor displays:
- The monitor does not display anything. User can display a signal of his choice here.

Graphics 2 Panel

Neither monitor displays anything. User can display a signal of his choice here.

Operating Mode

Description

Speed No Load

The No Load operating mode simulates rotation speed without electrical current. The mechanical torque applied by the turbine feeds the rotor. The resisting torque is determined solely by friction loss.

A simple model lets you define the torque according to the rotation speed. It should be noted, however, that the mechanical torque applied by the turbine is also dependant on rotation speed.

Synchronized

In synchronous network mode, resistance to mechanical torque is comprised of friction resistance torque and electrical torque, which is the sum of synchronization and damping torques.

These torques typify the reaction of the network synchronized AC generator to changes in operating conditions. The synchronization torque determines the natural frequency of a synchronized AC generator’s power oscillations. It is highly dependent on drive power.

The damping torque is generally low when the voltage speed governor is not equipped with a stabilizing circuit.

The diagram describes the equations that let you calculate synchronization and damping torques according to the natural oscillation frequency FN and the damping factor.

Islanded Operation

In Islanded operation, the friction resistance torque and the total electrical load for the Islanded counter the mechanical torque. The total load is comprised of the initial power generated in the previous operating mode and a range defined in the operating mode control panel.

This range comes into effect when in Islanded operation or when its value is changed while in Islanded operation.

Specialized Solutions Documentation

BERTA Certification Principles

Certification Principles

Certify_1 Button

Settings Panel

Graphic Panels

Graphics 1 Panel

Graphics 2 Panel

Graphics 3 Panel

Graphics 4 Panel

Dials Panel

Calibration Panel

Certify_2 Button

Operation Control Desk

Generic PID Speed Governor Panel

Classical Speed Governor

Servomotors Panel

Hydraulic Turbine Panel

Certify_3 Button

Command Desk to Actual Speed Governor Panel

Digital Signals From Actual Speed Governor Panel

Graphic Panels

Graphics 1 Panel

Graphics 2 Panel