perolofl's profile - activity

API psspy.progress takes a string as argument, not a real. You must convert the value to a string and also add a carriage return (\n).

psspy.progress(str(Qgen[i])+'\n')

Model LCFB1 can be used for secondary frequancy control of a machine. It is called as a Turbine Load Controller model, updating the power reference of the governor model.

Use inibrn and nxtbrn3, for example, to loop all branches and transfomers connected to ibus:

ibus = 154
ierr = psspy.inibrn(ibus, 2)
while True:
    ierr, jbus, kbus, ickt = psspy.nxtbrn3(ibus)
    if ierr>0: break

In Program Application Guide:

"All real load remaining on the bus after applying the specified percentages varies as the voltage is raised to the KP power."

In Models manual:

Record a python script while performing the study manually in the GUI.

Edit the script and insert a loop to perform the incremental change.

Example 1:

ierr, types = psspy.abustypes('TYPE')

will return 0 ['I'] since 'TYPE' is a valid string to API abusint.

Example 2:

ierr, types = psspy.abustypes(['TYPE','PU','VOLTAGE','EXNAME'])

will return 0 ['I', 'R', 'X', 'C'] since the arguments are valid strings to API abusint, abusreal, abuscplx and abuschar respectively.

Example 3:

ierr, types = psspy.abustypes(['TYPE','PU','VOLTAGE','EXNAME','XXX'])

will return 5 [None, None, None, None, None] since argument 'XXX' is not a valid string to API abusint, abusreal, abuscplx or abuschar. I.e., all supplied strings must be valid!!! The error code is 5 here since it is the fifth element in the list that contains the wrong string.

Use GOTO to jump to another location of the code, not to jump to the next line!!!! Read the example codes again in order to understand the use of GOTO. But again, avoid GOTO!

Your usage of GOTO statements is totally wrong. For example in mode 1-4 the model will always return at line 19, so the rest of the code is never executed. That's why the state and vars are not updated by the model.

Why are you jumping to the next line with a GOTO statement at line 22, 27, 32, 69, 83 and 90? I recommend you to study programming basics in order to structure the code in a correct way. Avoid GOTO in the code, it is not necessary in modern Fortran.

There are more errors:

Numtrm is not necessary since this is not a generator model. Remove line 12 and 13.

The DYDA record in mode 6 is not correct for a UDM.

L is used instead of N to index VAR at line 25

Have you implemented DOCU (mode 5) and DYDA (mode 6) in your model? If so, perform DOCU and DYDA and check if the model prints the reports.

What kind of model is it? How is it called? In Conet or is it a table-driven-model?

Have you initialised the simulation (STRT) before doing LIST?

The include statement just inserts the code in file comon4.ins into the source code. It contains declaration of variables and common blocks, for example CON, STATE, VAR, EFD, VREF used in the model.

BADMID is only needed if you have the option of extended term simulation, so you can, most probably, forget that function.

You need a Fortran compiler in order to compile and link the source code.

Add a VAR to a channel with the VAR/STATE channel selection tool. Menu: Dynamics - Define simulation output - Misc quantity. It is important to select "Network frequency dependence" option in "Dynamic simulation options".

Why shouldn’t the formula give accurate result when frequency changes? I have never used alt. 2 since I am using alt. 3.

Unfortunately, PSSE doesn't have any channel for branch current. I see at least three alternatives for you.

1. Calculate from line MVA and bus voltage. Add channels with line MVA flow and bus voltage magnitude. Use a function in plotbook to calcuate I = MVA / Vpu / base voltage / 1.73205 to get the current in kA.

2. Use a line relay model, e.g. TIOCR1, with dummy parameters and assign the model VAR containing the line current into a channel. The line current will be in pu.

3. Write a user written model that calculates the line current and assigns it to a VAR. Add a channel for the model VAR. This is how I solved it myself!

Out of topics!!!

According to the release notes, PLBVFU1 was added at 34.1!

Use API inibrn, nxtbrn and brnflo!

Google on how to write to text files in Python! The solution is there if you just search.

Yes, that is possible!

I have noted that there are many question in this forum regarding which API to use in order to perform a certain task. The method I prefer is to record a python script while performing the task manually in the GUI.

Stop recording and open the script. For example if I manually change Qload at bus 205 to 600 Mvar the recorded script will be:

psspy.load_chng_4(205,r"""1""",[_i,_i,_i,_i,_i,_i],[_f, 600.0,_f,_f,_f,_f])

Now I see which API is used to perform the change (loadchng4) and I can read about the API in the manual. Only the parameter values that I changed are written to the script and the other parameters are represented with their default values ( i for integers and _f for floats). For a data changing API this means that they are not changed, i.e. keeping their old values. For API adding new components, like loaddata_4, the default values will take the same values as for actitivty READ.

It is only necessary to enter the argument up to the last one to be changed. In my example I am changing the second real argument so the rest of the real arguments can be skipped:

psspy.load_chng_4(205,r"""1""",[_i,_i,_i,_i,_i,_i],[_f, 600.0])

Since I am not changing any integer arguments I can skip those defaults and just enter an empty list for the integer arguments:

psspy.load_chng_4(205,r"""1""",[],[_f, 600.0])

It is also possible to pass argument with their keyword name. In this case the second real is named realar2:

psspy.load_chng_4(205,r"""1""",realar2= 600.0)

Integer arguments are named intgar, for example

psspy.load_chng_4(205,r"""1""",realar2= 600.0,intgar3=6)

to change the third integer (zone number) to 6. Note that the order of keyword arguments doesn't matter. The integer argument can be given after the real argument.

Use API newcase_2!

For example to create an empty case with 100 MVA base and 50 Hz base frequency:

 psspy.newcase_2([1,1], 100.0, 50.0,"","")

You don't understand the basics of PSSE. You can only add a generator at a Plant, not at an ordinary type 1 bus.

First create a plant with:

psspy.plant_data(601,0,[ 1.0, 100.0])

The bus frequency is calculated from the change in bus voltage angle. A filter is applied to smooth the frequency result, using a 0.04 s time constant for the filter. The frequency filter time can be changed in "Dynamic Solution Parameters".

This forum is for PSSE users...

Yes, Pmax is here the maximum Pmech limit in MW. I have no reference for the formula, I found it out myself many years ago...

In HYGOV the governor position p.u. value differ from the generator power p.u. value due to qNL and At parameters.

Calculate Gmax in the following way:

Gmax = Pmax/(Mbase*At) + qNL

For example if At = 1.2 and qNL = 0.08:

Gmax = 900/(1200*1.2) + 0.08 = 0.705

Transmission lines have different ratings for different ambient temperatures. Also different rating for normal operation and short time overload operation after contingencies. There are equipments in the breaker bay with different current rating, e.g. breaker, current transformer, switches.

From rev 34 there are twelve ratings, which is enough for the need of most users. You just use the number of ratings that are necessary for you needs.

You have to change input mode for the Command Line Input window from "PSSE Response"" to "Python".

It seems to be an issue with your dyre-file since PSSE is crashing.

Dyre_new replaces old dynamic models with the new models defined in the dyre-file. PSSE will then allocate the new model parameters at the end of the CON, VAR, STATE and ICON vectors. After doing that 900 times you reached the maximum possible index for the a vector.

Open the snapshot again before doing dyre_new.

EDIT: In my answer above I mixed up dyrenew with dyreadd. My discussion above is valid for dyreadd but you are using dyrenew so there should not be any problems with the vectors.

Why are you reading in models with dyre_new before every simulation? What parameters are you changing in your simulations? You are not following the normal procedure for dynamic simulations.

EDIT 2: I would recommend you to move all code from line:

#Parameters

to line:

ierr = psspy.bus_frequency_channel([-1, bus])

before the loop, since the same raw-file and dyr-file is used in all simulations. Then save the converted saved case and the prepared snapshot (including all dynamic data and channels).

psspy.save(xxx)
psspy.snap(yyy)

Inside the loop:

Read the converted case and restore the snaphot at the beginning, so you will start each simulation with same data (case and snapshot).

psspy.case(xxx)
psspy.rstr(yyy)

In this way dyre_new will only be executed once!!!

Change the phase shift of the generator step-up transformer with 20 degrees. For example use API:

psspy.two_winding_chng_4(3008,3018,r"""1""",[],[_f,_f,_f,_f,_f, 20.0])

to change for generator at bus 3018 in savnw.sav.

I don't understand. In a dynamic simulation the voltage angle is a result at each time step and not input data that can be changed by the user.

The rotating energy for a generator is Hi*Si, where Si is nominal MVA rating. The formula is RoCoF = deltaP / (2*sigma(Hi*Si)) * fn [Hz/s]. The actual electrical power Pi for the generators does not affect the RoCoF.

Connect the fault at the dummy bus so all fault current will flow on the ZIL.

Only the positive sequence network is modeled in dynamic simulation. To plot the fault current, split the bus and insert a dummy bus with a ZIL between the buses. Add line channel with MVA for the ZIL. Divide the channel with Ubase and sqrt(3) in order to plot the line currrent.

It cannot be simulated in PSSE.

Read Chapter Model Writing in Program Operation Manual!

Menu: Dynamics - Solution parameters... - DELT

or

psspy.dynamics_solution_param_2([_i,_i,_i,_i,_i,_i,_i,_i],[_f,_f, 0.001,_f,_f,_f,_f,_f])

Fast valving in TGOV2 follows the scheme defined by Ta, Tb and Tc. Maybe it is possible to affect the scheme by changing the parameters during the simulation.

PSSE does not have any facility to ramp EFD. However it can be done with some code in the CONEC file or with a user-written model.

Unfortunately there is no channel for line current. One workaround is to add a channel with MVA flow and divide with Ubase and sqrt(3) when plotting.

Assign the CON-value to a VAR in the following way:

1. Find out the number of the CON you want to plot with DOCU. Let us assume the number is 1234.

2. Create CONEC and CONET subroutines with DYRE if you don't have them already.

3. Enter the following line in the CONEC file before the RETURN statement (make sure the VAR number is higher than the highest number used in the snapshot):

   VAR(99999) = CON(1234)

4. Compile CONEC and CONET and link dsusr.dll.

5. Load dsusr.dll into PSSE.

6. Add a new VAR channel for the VAR number used in step 3. E.g. psspy.var_channel([-1,99999],"STATCOM VREF")

7. Save the snapshot.