creat .cpp & .dll code

[aro]

[Frank Tuffner]

Hello Aro,

In the file you linked, none of your constant_current loads have the GFA enabled. If I modify one, it works perfectly fine:

object load:112 {
     name 112;
     phases "AN";
     frequency_measure_type PLL;
     GFA_enable true;
     flags DELTAMODE;
     voltage_A 2401.7771;
     voltage_B -1200.8886-2080.000j;
     voltage_C -1200.8886+2080.000j;
     constant_current_A 8.3272-4.1636j;
     nominal_voltage 2401.7771;
    object recorder {
        property "GFA_status,measured_frequency,GFA_trip_method";
        interval 1;
        flags DELTAMODE;
        file "GFAtest_status_out.csv";
    };
}

If you run that in your simulation, you clearly see it trips offline at 13:00:05.658000, due to an over-frequency issue.

For your simulation, there's clearly an interaction going on between the GFA and CVR functionality. With the GFAs off, the frequency dips far enough down to trigger the GFAs (if they were active, which when they are, you see all of them disconnect with under-frequency at the end). This can cause some disruptions in how the CVR controller is working, especially relating to the coefficients. The CVR functionality for the DGs is still highly experimental, so you may be encountering an edge case or unstable case.

Unfortunately, the best bet is to keep trying different parameters or setpoints for the CVR and GFAs, as well as some of the generator parameters. Dynamic simulations can be a bit finicky and sensitive, so tweaking your parameters slightly may cause the system to suddenly work perfectly. The may be an issue with the CVR implementation too (if I have a chance, I may look into this further).

-Frank

[aro]

Hello Dear Frank

You were right. ( the GFA works on constant_current loads ,...)
About using the GFA and CVR simultaneously: I changed the parameters and the simulation resulted well. (CVR_Kd1 200---->CVR_Kd1 10)

Thank you very much

-aro

[aro]

Hello again Dear Frank,

in this link:
Why the voltage decrease from the set value(0.05)?
and
Is the node151 voltage, the average voltage of the three-phase?(in article)

Thank you

-aro

[Frank Tuffner]

Hello Aro,

For the voltage decrease, the 0.05 value is the limit to which the CVR functionality is "allowed to move". During a transient, especially if the system is overloaded (I didn't look at your file too closely), the conditions may pull the voltage lower. The CVR and exciter are working to keep it withing the 0.05 band, but are not operating fast or properly enough to do that. You could try reducing load or adjusting the CVR and exciter parameters to get a better result.

Regarding the paper, I don't recall how Fig. 8 was generated, but I would assume it is the average (positive sequence) voltage for node 151. If not, it may just be phase A, since that was probably the easiest to plot.

-Frank

[aro]

Hello Dear Frank

Thank you very much

-aro