Thread Subject: Dynamic Model of a Synchronous Generator

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

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.

"Frank W." <yohansan@web.de> wrote in message <hd8t10$s1l$1@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

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

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

> The mentioned phase angles in the initial condtions refer to the currents. The phase difference between grid and plant cannot be specified directly.<

Of course, it can. One only has to subtract/add a certain angle from 'th(deg)' and 'pha,phb,phc (deg)' in order to achieve a certain phase difference between the grid and the plant.

Hi Frank,

Thanks for all your replies. I have some question regarding manual control in Simulink. Is it possible to have some blocks in Simulink through which it is possible to control, meaning increase or decrease a value manually during the simualtion time? Basically it deals with real time control of a process in Simulink manually.

Thanks and Regards,
badri

>I have some question regarding manual control in Simulink. Is it possible to have some blocks in Simulink through which it is possible to control, meaning increase or decrease a value manually during the simualtion time? Basically it deals with real time control of a process in Simulink manually.
>
Hi,
you can use blocks (i.e. ramp signal to increase speed/voltage in case you still work on the synchronising issues) to change the value during running the simulation. Other people have also used self built user interfaces (GUIs) for interaction with simulink models - I cannot give any help about this.
I presume with 'real time control' you mean that the simulation is running on your machine and you interact with that simulation and watch what happens. Or do you want the simulation being executed in real time (i.e. simulator for training operators)?
Regards
Frank

Hi Frank,

Yes i wanted to know abt GUI control of the running simulation which unfortunately you could not answer.

 I also wanted to know about the simulation being executed in real time for training operators as you mentioned in your reply. Is it possible to do that in Simulink.?

Regards,
badri

> I also wanted to know about the simulation being executed in real time for training operators as you mentioned in your reply. Is it possible to do that in Simulink.?
>
Hello,
for real time execution you would need hardware that is able to process in real time (Windows operating systems are not). I recommend contacting The Mathworks about their xPC target product because this is designed for real time processing. I do not know this product (apart from watching one or two of their webinars) but I think I came across that xPC target and SimPowerSystem are not compatible. Therefore please contact The Mathworks.
About designing a GUI to interact with Simulink I suggest opening a new thread and tagging it as ' designing GUI' and 'simulink' because this is no longer related to the synchronous generator. Good luck!
Regards
Frank

Hallo Frank,

Thanks for your help. I will do as you suggested.

Regards,
Badri