Dynamic Model of a Synchronous Generator
in [Matlab]
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From: Badri Pattabiraman on 20 Oct 2009 04:56 Hallo, I am making a model of Synchronous Generator to be used in a power plant. Subsequently i have to design my auxiliary loads in power plant and the power network. First i have to build the Synchronous Generator model in Simulink. But finally i have to built it in another simulator which has only simple componenets like intergerator, multiplier, Adder etc. In SimpowerSystems, there exist a model for Synchronous machine. But this exist as a single block. I would like to know the details behind this single block. What is basic model on which this block works.? I have collected the necessary technical datas for the Generator in dq reference frame and also aware of the dynamic equations. But how to model this to get electrical power as output? If somebody can throw some light on this modelling, it would be really great. Also any references and links are welcome. Thanks, badri
From: Frank W. on 9 Nov 2009 06:05 Hello, > In SimpowerSystems, there exist a model for Synchronous machine. But this exist as a single block. I would like to know the details behind this single block. What is basic model on which this block works.? > In order to get the detailed model of the synchronous machine block you select the model block (left click) and then right clicking on it. A Menu will pop up. In this menu you select the command 'Look under Mask'. This will open another Simulink Window in which the masked subsystem is displayed. In this window you can double click on the electrical and mechanical subsystems to have the implementation of the equations in dq reference frame. > I have collected the necessary technical datas for the Generator in dq reference frame and also aware of the dynamic equations. But how to model this to get electrical power as output? If somebody can throw some light on this modelling, it would be really great. Also any references and links are welcome.> The actual electrical power output (real/active power and reactive power) will depend on the load (including other plants and maybe an electrical grid) attached to that model. In case of a more complex system (i.e. not a simple RLC load but other AC machines, compensator circuits, other synchronozs machines) many more equations must be solved know as the 'load flow' calculation. The input to the synchronous mchine model is either rotational speed or active power by a turbine or motor rotating the shaft. For modelling synchronous machines I found the book 'Dynamic Simulation of electrical machines using Simulink' by C.M. Ong helpful. You find some the models under http://www.mathworks.com/matlabcentral/fileexchange/9941-dynamic-simulations-of-electric-machinery-using-matlabsimulink Also the book 'Power System Stability and Control' by P. Kundur might be of help when modeling electrical power systems. Kind regards F.W.
From: Badri Pattabiraman on 13 Nov 2009 11:37 "Frank W." <yohansan(a)web.de> wrote in message <hd8t10$s1l$1(a)fred.mathworks.com>... > Hello, > > > In SimpowerSystems, there exist a model for Synchronous machine. But this exist as a single block. I would like to know the details behind this single block. What is basic model on which this block works.? > > > In order to get the detailed model of the synchronous machine block you select the model block (left click) and then right clicking on it. A Menu will pop up. In this menu you select the command 'Look under Mask'. This will open another Simulink Window in which the masked subsystem is displayed. In this window you can double click on the electrical and mechanical subsystems to have the implementation of the equations in dq reference frame. > > > I have collected the necessary technical datas for the Generator in dq reference frame and also aware of the dynamic equations. But how to model this to get electrical power as output? If somebody can throw some light on this modelling, it would be really great. Also any references and links are welcome.> > The actual electrical power output (real/active power and reactive power) will depend on the load (including other plants and maybe an electrical grid) attached to that model. In case of a more complex system (i.e. not a simple RLC load but other AC machines, compensator circuits, other synchronozs machines) many more equations must be solved know as the 'load flow' calculation. The input to the synchronous mchine model is either rotational speed or active power by a turbine or motor rotating the shaft. > > For modelling synchronous machines I found the book 'Dynamic Simulation of electrical machines using Simulink' by C.M. Ong helpful. You find some the models under > http://www.mathworks.com/matlabcentral/fileexchange/9941-dynamic-simulations-of-electric-machinery-using-matlabsimulink > Also the book 'Power System Stability and Control' by P. Kundur might be of help when modeling electrical power systems. > > Kind regards > F.W. Hallo Frank, Thanks for the reply. I am able to explore the model now. I am going to have Grid along with other Generating station on the my load side. That should make things llittle bit complicated. Anyway I also want to know if the process of Synchronisation can be simulated here. When the Generator operates in Island operation, its not yet conencted to grid. When the synchrnonization takes place, load flow happens. Is it possible we simulate both Island operation and operation with grid using the same model? Thanks and Regards, badri
From: Frank W. on 16 Nov 2009 04:52 Hello, <Anyway I also want to know if the process of Synchronisation can be simulated here. When the Generator operates in Island operation, its not yet conencted to grid. When the synchrnonization takes place, load flow happens. Is it possible we simulate both Island operation and operation with grid using the same model?> This should be possible. The crucial part will be setting the conditions of the grid and the island prior to breaker closure. The Block Parameters Dialog of the synchronous machine model allows specifying the intial condtions of the synchronous machine (vector 'Init. cond.'). So I would first perform a load flow with the 'powergui' block with the breaker between grid and plant open. This will set the initial conditions in your model on grid and plant side of your model (Especially when you have a plant load attached to the generator this is the easiest way to set the mechanical power input 'Pm' of the machine correctly). You can then change the phase angles ('pha,phb,phc(deg)') of your plant generator to the desired value and start simulation with the breaker closing shortly after simulation start. Kind regards Frank
From: Frank W. on 16 Nov 2009 05:53
Sorry, I made a mistake. The mentioned phase angles in the initial condtions refer to the currents. The phase difference between grid and plant cannot be specified directly. Kind regards Frank |