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This chapter describes the procedure to follow when using the BERTA On-Site Tests application.

The RT-LAB BERTA test bench carries out tests on power plant speed governors using simulation functions, such as the islanded grid operating mode. AC generator current and voltage signals from the current and voltage transformer secondary windings are converted into low voltage signals.

These signals are sent to the appropriate analog/digital converters of the BERTA test bench.

These alternating low voltage signals are calibrated beforehand so as not to exceed the saturation thresholds of the converters.

An option allows using the test bench in full simulator mode with the speed governor and AC generator models of a virtual grid.

Start-Up

For on-site tests, make all the necessary connections described in the recommended procedure.

Power Plant Test Setup Diagram

TestDrive Main Screen

The main screen consists of three sections:

Main Screen

The Control panel toolbar on the left provides access to a series of panels (Gr. 1 to 5, Gr. 6 to 10, Gr. 11 to 15, Gr. 16 to 21, Controller, Interface, Islanded Units, Islanded Loads, Virtual Grid).
Refer to the Control Panel Toolbar in the General Introduction for more details.
The Graphic panel in the middle displays acquisition signals.
The Command panel toolbar on the right consists of command buttons and fields displaying the progress of the simulation. Refer to the Command Panel Toolbar section for more details.

Control Panel Toolbar

The Panels tab in the Control panel toolbar accesses the following panels:

Gr. 1 to 5
Gr. 6 to 10
Gr. 11 to 15
Gr. 16 to 20
Controller
Interface
Islanded Units
Islanded Loads
Virtual Grid

Panels Tab in Control Panel Toolbar

Command Panel Toolbar for Graphic Panels 1 to 5 and 11 to 21

Command Panel Toolbar	Toolbar Buttons	Description
	GO Acquis	Starts signal acquisition and recording. Click once to start (bright green indicator) and click again to stop (dark green indicator)
	GO Disturbance	Starts the insert of the disturbance. Click once to start (bright green indicator) and click again to stop (dark green indicator)
	Reset dFreq Sim	Resets the simulated frequency deviation to zero and resets the initial conditions of the virtual generating units. Switch to the right and hold for 3 seconds
	Mean PS values	Computes the mean values of power and main servomotor position during the period defined in the Period P S field
	Period PS	Mean speed value. Computes the mean value of the rotating speed during the period defined in the Period Speed field
	Period Speed	Mean speed value. Calculates the mean value of the rotation speed during the period defined in the Period Speed field
	Toolbar Fields	Description
		The computing time period for the mean values of power and main servomotor position. Refers to command Mean P S values
		The computing time period for the mean value of the rotating speed. Refers to command Mean speed value
	Test No	Increments the test number by one and the recording file name suffix each time GO Acquis is disabled. There is a 10 seconds delay to allow for the closing of the recording file.
	File status	Shows the recording file status. (Free or full)
	Overruns	Increments by one each time the total processing time is longer than the requested time step
	Computing time	The time required by the workstation to complete one full cycle of all the computations, in μs
	Idle time	Time margin between each time step and the total computing time, in μs
	Time Step	Actual time step, in μs
Acquisition Time		Displays the acquisition time, as shown in the picture on the left

Command Panel Toolbar: Graphic Panels 6 to 10

Command Panel Toolbar	Toolbar Buttons	Description
		Synchronization switch. Click to synchronize the voltage signals generated by BERTA with the grid voltage. Observe the voltage signal curves on graphics 6
		Relay command switch to the speed governor. Toggles the speed governor input signal from the grid frequency to BERTA and vice-versa
		Actual (hardware) relay status. Indicates the source of the frequency signal: grid (green) or BERTA (red). A blinking signal signifies that either there is a defect on the relay, either it is not connected
		Forcing switch. In an emergency case, forces the relay to toggle immediately, without waiting for the synchronization
		For the selection of the tested unit network: the virtual network or the actual network. (Real test in a powerhouse)
	GO Acquis	Starts signal acquisition and recording. Click once to start (bright green indicator) and click again to stop (dark green indicator)
	GO Disturbance	Starts the insert of the disturbance. Click once to start (bright green indicator) and click again to stop (dark green indicator)
		Reset dFreq Sim. Resets the simulated frequency deviation to zero and resets the initial conditions of the virtual generating units. Switch to the right and hold for 3 seconds
	Toolbar Fields	Description
	Test No.	Increments the test number by one every time GO Acquis is disabled
	File Status	Shows the file status where the tests are being saved.
	Acquisition Time	Displays the acquisition time

Graphic Panels

The Panels tab in the Control panel toolbar provides access to graphic panels each with two monitors (top and bottom). Signal assignments are preset but can be changed. For more details, refer to Creating or Changing Signal Assignments.

Tab	Monitor Position	Signal Name	Signal Description
GRAPHIC PANELS 1 to 5
Graphic 1	Top	Vab	Generator unit phase to phase voltage A-B (p.u.)
		Sim Volt A	Simulated phase A voltage at desired frequency (p.u.)
	Bottom	Ia, Ib, Ic	Phase currents (p.u.)
Graphic 2	Top	Sim dFreq	Simulated frequency deviation (p.u.)
	Bottom	Sim Pelec Total (pu)	Simulated total electric power, including all virtual loads of islanded grid (p.u. on total MVA)
		Sim Pmec Total (pu)	Simulated total mechanical power, including all virtual generating units of the islanded grid (p.u. on total MVA)
Graphic 3	Top	Servo1	Main servomotor stroke (position) (p.u.)
		Mean Servo 1	Mean servomotor stroke during period P S
		Servo 2	Second servomotor stroke or signalNo. 11
	Bottom	Pelec T U	Measured electric power of the tested unit, including resistive losses of the stator
		Mean P	Mean mechanical power of the tested unit during period P S
		Pmec T U	The mechanical power of the tested unit as estimated by BERTA
Graphic 4	Top	Servo 1	Main servomotor stroke (position) (p.u.)
		Pmec T U	The mechanical power of the tested unit as estimated by BERTA
	Bottom		Free
Graphic 5	Top	Pelec T U	Measured electric power of the tested unit, including resistive losses of the stator
		P rotor virtual	Resistive power of rotor (product of electrical torque and rotational speed) of virtual grid AC generating unit
	Bottom	Pmec T U	The mechanical power of the tested unit as estimated by BERTA
		Pmec Virtual	The mechanical power of the virtual grid turbine

GRAPHIC PANELS 6 to 10
Tab	Monitor Position	Signal Name	Signal Description
Graphic 6	Top	Va	AC generator voltage phase A (p.u.)
		Sim Volt A	Simulated voltage phase A at the desired frequency (p.u.)
	Bottom	Va	AC generator voltage phase A (p.u.)
		Ia	AC generator current phase A (p.u.)
Graphic 7	Top	Sum I	Sum of currents for the three phases NOTE: This sum must be zero. or near this value. If not, check connections and calibrations.
		Sum V p-p	Sum of voltages phase to phase (p.u.) NOTE: This sum must be zero. or near this value. If not, check connections and calibrations.
	Bottom	Va rms	Rms voltage of phase A (p.u.)
		Ia rms	Rms current of phase A (p.u.)
Graphic 8	Top	Sim Pelec Total	Total electrical power simulated, including all the virtual loads of the islanded grid (p.u. on total MVA)
		Sim Pmec Total	Total mechanical power simulated, including all the virtual generating units of the islanded grid (p.u. on total MVA)
	Bottom	Pelec T U	Electrical power estimated by BERTA
		Pmec T U	Mechanical power estimated by BERTA
Graphic 9	Top	Sim Freq	Simulated frequency (p.u.)
		Estimated speed T U	Estimated speed of tested AC generator (p.u.)
	Bottom	Va Vb Vc	Three phase voltages of tested AC generator (p.u.)
Graphic 10	Top		Free
	Bottom		Free

GRAPHIC PANELS 11 to 15
Graphic 11	Top	Va	AC generator voltage phase A (p.u.)
		Vab	AC generator phase to phase voltage A-B (p.u.)
		HV 4	High voltage, signal No. 4 from AD (p.u.)
	Bottom	Vb	AC generator voltage phase B (p.u.)
		Vbc	AC generator phase to phase voltage B-C (p.u.)
		HV 5	High voltage, signal No. 5 from AD (p.u.)
Graphic 12	Top	Vc	AC generator voltage phase C (p.u.)
		Vca	AC generator phase to phase voltage C-A (p.u.)
		HV 6	High voltage, signal No. 6 from AD (p.u.)
	Bottom		Free
Graphic 13	Top	Va Vb Vc rms	rms voltages from tested AC generator (p.u.)
	Bottom	Ia Ib Ic	rms currents from tested AC generator (p.u.)
		Pm thermal
		Pm gasturbine
Graphic 14	Top	MW Total Hydro	Total virtual hydraulic production (MW)
		MW Total Thermal	Total virtual thermal production (MW)
		MW Total Gas	Total virtual gas turbine production (MW)
	Bottom	MW Total Pmec	Total mechanical power (MW)
		MW Total Load	Total load before disturbance (MW)
		MW Total Pelec	Total electrical power (Load) (MW)
		MW Pmec T U	Mechanical power of tested AC generator (MW)
Graphic 15	Top		Free
	Bottom		Free

GRAPHIC PANELS 16 to 21
Graphic 16	Top	U1 Hydro Pm (MW)	Virtual Hydro Unit 1 Pm MW
		U2 Hydro Pm (MW)	Virtual Hydro Unit 2 Pm MW
		U3 Hydro Pm (MW)	Virtual Hydro Unit 3 Pm MW
		U4 Hydro Pm (MW)	Virtual Hydro Unit 4 Pm MW
		U5 Hydro Pm (MW)	Virtual Hydro Unit 5 Pm MW
	Bottom	U1 Hydro Gate	Virtual Hydro Unit 1 gate
		U2 Hydro Gate	Virtual Hydro Unit 2 Gate
		U3 Hydro Gate	Virtual Hydro Unit 3 Gate
		U4 Hydro Gate	Virtual Hydro Unit 4 Gate
		U5 Hydro Gate	Virtual Hydro Unit 5 Gate
Graphic 17	Top	U1 Thermal Pm (MW)	Virtual Thermal Unit 1 Pm MW
		U2 Thermal Pm (MW)	Virtual Thermal Unit 2 Pm MW
		U3 Thermal Pm (MW)	Virtual Thermal Unit 3 Pm MW
		U4 Thermal Pm (MW)	Virtual Thermal Unit 4 Pm MW
		U5 Thermal Pm (MW)	Virtual Thermal Unit 5 Pm MW
	Bottom	U1 Thermal Gate	Virtual Thermal Unit 1 valve
		U2 Thermal Gate	Virtual Thermal Unit 2 valve
		U3 Thermal Gate	Virtual Thermal Unit 3 valve
		U4 Thermal Gate	Virtual Thermal Unit 4 valve
		U5 Thermal Gate	Virtual Thermal Unit 5 valve
Graphic 18	Top	U1 Gas Pm (MW)	Virtual TAG Unit 1 Pm MW
		U2 Gas Pm (MW)	Virtual TAG Unit 2 Pm MW
		U3 Gas Pm (MW)	Virtual TAG Unit 3 Pm MW
		U4 Gas Pm (MW)	Virtual TAG Unit 4 Pm MW
		U5 Gas Pm (MW)	Virtual TAG Unit 5 Pm MW
	Bottom	U1 Gas Valve	Virtual TAG Unit 1 Valve
		U2 Gas Valve	Virtual TAG Unit 2 Valve
		U3 Gas Valve	Virtual TAG Unit 3 Valve
		U4 Gas Valve	Virtual TAG Unit 4 Valve
		U5 Gas Valve	Virtual TAG Unit 5 Valve
Graphic 19	Top	Load 1 MW	Rated Load 1 MW
		Load 2 MW	Rated Load 2 MW
		Load 3 MW	Rated Load 3 MW
		Load 4 MW	Rated Load 4 MW
		Load 5 MW	Rated Load 5 MW
	Bottom	Ch. 1 Shedding MW	Shedded MW, Load 1
		Ch. 2 Shedding MW	Shedded MW, Load 2
		Ch. 3 Shedding MW	Shedded MW, Load 3
		Ch. 4 Shedding MW	Shedded MW, Load 4
		Ch. 5 Shedding MW	Shedded MW, Load 5
Graphic 20		AD Signal No.	Signals 12 to 21 from ADs (V or mA)
Graphic 21		AD Signal No.	Signals 22 to 32 from ADs (V or mA)

BERTA On-Site Tests