Updated the data for p0 for PV, but no impact on TDS results

[TheASingh]

Hello @cuihantao, @jinningwang,

I want to see the impact of p0 of PV on TDS results in DGPRCT1 (Togglers are disabled) use case. I followed the following steps:

1. Ran the TDS for 5 seconds.
2. Updated the p0 value of PV using the below command:
   ss.PV.alter("p0", 2, 0.1)
3. Continued the TDS for 10 seconds.
4. Reset the p0 value of PV to original using the alter command.
5. Continued the TDS for 20 seconds.
6. On plotting the graph for BusFreq, there were all straight lines as shown below:

FYI, I have also tried updating p value of PV on step 2, but no impact on the plot.
Please guide me, where I'm going wrong.

Thanks

[cuihantao]

@jinningwang might be able to help you.

[jinningwang]

Hi there,

I understand you want to see the impact of p0 of PV on TDS results.
Parameter p0 refers to the active power setpoint, which is used as the initial value of power flow calculation. TDS will take the power flow solution and do the dynamic simulation. Once the dynamic simulation starts, p0 will no longer impact the system.
Changing the p0 value before running TDS should be able to make an impact.

Regards,
Jinning

[jinningwang]

Hi Singh, @TheASingh

I checked the documentation and tested the case you said, I realized that I have previously misled you a little bit.

Q1: In the given exaple you can find that, the setpoint of governor is modified by paux0: https://github.com/cuihantao/andes/blob/develop/examples/8.%20change-setpoints.ipynb
Sorry for my previous misled you playing with paux.

The detailed reason is that: the alter method defined in the model is used to modify the values of service or parameter, as described in the documentation: https://docs.andes.app/en/stable/moduledoc/andes.core.html?highlight=alter#andes.core.model.Model.alter
It means that we should modify paux0 rather than paux, since paux0 is a ConstService whereas paux is a Algeb, as described in the documentaion: https://docs.andes.app/en/stable/groupdoc/TurbineGov.html#tgov1

Q2: paux0 is the common ConstService used by group TurbineGov as the initial value of paux. It means that as long as there is a governor model, you can change the active power setpoint by altering the value of paux0. It is common and reasonable that a generator is equiped with a governor.

Hope this helps you out.

Regards,
Jinning

[TheASingh]

Thank you very much @jinningwang,

Now, after altering paux0, I'm able to see the impact on the plots.
Please clear my doubts on the following items:

1. Before altering the paux0 value, I checked all the TGOV1s were having zero values for paux0 as shown below.

   

   And p0 of the PV is let's say is 0.3. Then in order to decrease the active power setpoint, what value should I set to paux0 (as it already is
   zero)?

2. If there is no governor attached to a generator, is it possible to change its active power setpoint dynamically?

3. Also in the DGPRCT1 use case, there are only three governors but generators are five. It means two generators do not have governors. Then how their active power setpoint can be updated?

Regards,
A Singh

[jinningwang]

1. It is also acceptable to set negative values for paux0. You can check the control diagram of TGOV1, which will give you a better clue of the meaning of those variables: https://www.powerworld.com/WebHelp/Content/TransientModels_PDF/Generator/Governor/Governor%20TGOV1.pdf
2. It is possible, by playing with the tm0 which is the initial value of mechanical torque: https://docs.andes.app/en/stable/groupdoc/SynGen.html?highlight=GENROU
3. Same to Q2.

Jinning

[TheASingh]

Thanks Jinning, it worked for me.

I changed the value of tm0 of GENROU_2 from 0.4 to 0.9. When I plot a graph for Pe, lines were oscillating as shown below.

Is it correct? If yes, then please explain little bit for my understanding.

Regards,
A Singh

[jinningwang]

I think it is correct. The oscillation is reasonable because the power increase is large.
I don't know what happened at 10s, it looks like protection is triggered or something is tripped.

Regards,
Jinning