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2020-09-23 12:50:24 -0500 commented question Dynamic Simulation in PSS/E 35 and PSS/E Explore

Maybe you should present the progress window output.

2020-09-23 06:24:21 -0500 answered a question When i playback, voltage magnitudes are correct but frequencies are not

The bus voltage frequency is calculated from the voltage angle with a filter of normally 40 ms (four time steps). That may explain the lag you see.

2020-09-23 04:16:12 -0500 answered a question Do dynamic simulation several times in one py file

Initialise PSSE before the loop and perform case and Predyr before the if-statements.

psspy.psseinit(10000) #initialize PSSE
for i in range(1,16):"""C:\Users\bbbb4\Downloads\112L-150M.sav""")
    if i==1:#case 1
        #### here's the code of event 1 ####
    if i==2:#case 1-1
        #### here's the code of event 2####
2020-09-21 14:12:20 -0500 answered a question Accessing fetch routines using GDIF

Unfortunately, the python recording of activity GDIF is not working (33.12.2). I propose you try activity DIFF instead. Start recording and perform the activity from GUI (File - Compare…).

Open and study the created python script in a texteditor, and read about diff in API manual.

2020-09-21 08:46:44 -0500 answered a question .dll loaded in PSS/E library not visible in .dyre

What do you mean not visible in .dyre? Can't you see the model in dynamic spreadsheet after reading the dynamic raw data file with DYRE? If so, check for reading error messages in progress window. It might be that the model wasn't read due to an error in the model record in the .dyr file.

The DLL file has nothing to do with the visibility of model calls in the spreadsheets.

2020-09-18 14:33:55 -0500 commented answer PV+Battery REPCA model

You have to write your own model or use two separate REPCA.

2020-09-18 12:02:30 -0500 commented answer Does PSS/E provide any functionality to auto-correct device limit violations during dynamic simulation initialization?

The idea is to update governor GMAX and GMIN to the same MW-value as PMAX and PMIN in the saved case.

2020-09-18 11:48:44 -0500 commented answer Does PSS/E provide any functionality to auto-correct device limit violations during dynamic simulation initialization?

Use amachint and amachchar to get lists with all generators. Loop the lists and get governor model name with mdlnam. Get CON starting index with mdlind. Use dsrval to get the CON value for GMAX and GMIN. Update those values, if necessary, with change_con if governor limits are too narrow.

2020-09-18 10:40:40 -0500 answered a question Does PSS/E provide any functionality to auto-correct device limit violations during dynamic simulation initialization?

The only auto-correct PSSE can do is to net in-service generators with missing generator model.

There is no problem to write a script for auto-correction. I have done something similar that updates the governor limits based on Pmax in saved case.

However, for exciter limiter violations I prefer to solve it manually, since almost always the problem lies in wrong load flow data, e.g., wrong Q-limits, solved without Q-limits, wrong Mbase, etc. For a correctly initialised exciter model, Emax should be well above the calculated field voltage (Efd).

2020-09-18 10:29:54 -0500 answered a question How would you include currents from load/generation in calculating the bus current?

There is no such API available. You can write your own function that returns the load or machine current calculated from the MVA load and the bus voltage.


As an example, I wrote a script that plots the complex currents in a vector plot. See example below for bus 201 in savnw network. There are three lines, one 2W-transformer and one fixed shunt at the bus. The bus voltage is the reference angle (0 degrees).

image description

2020-09-17 02:51:00 -0500 answered a question PV+Battery REPCA model

No, you cannot control two sources with REPCA model.

2020-09-17 02:44:19 -0500 answered a question REPCAU two generators

You should set both setpoint individually.

2020-09-16 02:51:03 -0500 answered a question How to simulate an inverter commutation failure in a two-terminal dc link?

What you see in PSSE is the bypass of the inverter, not the effect on the HVDC of a commutation failure. On the AC side the commutation failure is modeled with a shunt. You need a Pscad-study to see the dynamics of the link during a commutation failure.

2020-09-16 02:15:49 -0500 answered a question Monitoring VAR and STATES - Dyn simulation





Edit: The starting index for plant model are calulated with:

ierr, index = psspy.mdlind()

The starting index for wind model are calculated with:

ierr, index = psspy.windmind()

See the API manual for the arguments of the functions.

2020-09-09 09:14:11 -0500 answered a question Critical Clearing time calculation

Just supervise the rotor angle and check if the generator goes out of step, i.e., as you mentioned above.

2020-09-09 09:10:12 -0500 commented answer Switching off turbine governor model for dynamic stability

It is much better to disable the model…:-)

2020-09-09 05:35:43 -0500 answered a question How to change the metrical units on the pmtmlc file

Isn't it just to change to write access for the file???

2020-09-09 05:33:02 -0500 answered a question Network not converged at TIME = -0.02 despite initial conditions check being okay

Activate the convergence monitor at initialization. You will then see which bus has the largest mismatch.

2020-08-27 09:38:22 -0500 answered a question How to find weak voltage buses after a larger generation loss during dynamic simulation?

You can report all buses with voltages below a certain limit, for example 90% voltage:

psspy.vchk(0,1, 0.9, 2.0)
2020-08-27 01:31:28 -0500 answered a question Can i get locational marginal prices using PSS/E OPF module?

I don't know about OPF but in PSSE the cost curves are given in economic dispatch files. See Program Operation Manual and "Performing Unit Commitment and Economic Dispatch".

An economic dispatch file has the file extension .ecd.

2020-08-27 01:20:59 -0500 answered a question Unbalance fault

Only the positive sequence is modelled in dynamic simulations. An unbalanced fault is then modelled with an equivalent positive fault admittance, so the positive sequence voltage will be correct during the fault.

In your case the positive sequence voltage is calculated to be 80% during the fault.

2020-08-25 03:43:38 -0500 commented answer Power flow results of SMIB in PSS/E do not match the hand calculations

2. Yes, it is the reactance of the machine.

2020-08-25 00:48:20 -0500 answered a question Missing CON descriptions for user-defined model

A DLL-file for rev 33 cannot be used in rev 34. The user model must be compiled and linked again.

2020-08-24 03:44:02 -0500 answered a question How to link two models from PSSE model library using CONEC

You can try the following line directly in CONEC:


where L is the first VAR number of SVSMO1U2 and MCHNINDX is the machine index for the dummy generator. This should update the POD input of SVSMO1U2 with the signal from STBSVC.

2020-08-24 02:15:37 -0500 commented answer How to add a extra digit on the bus numbers in PSS/E

Yes, but it is much easier to use bsnm as shown in the answer Aug 17, 2018.

2020-08-24 02:09:05 -0500 answered a question Power flow results of SMIB in PSS/E do not match the hand calculations
  1. Xsource must be low for an infinite bus, as ffl wrote. But, Zsource is not used in load flow so it doesn't affect the steady state voltage.
  2. Transient reactance is only applicable in dynamics, not in load flow.
  3. The hand calculation is wrong, because the PSSE results are correct.
2020-08-19 09:46:24 -0500 commented answer Retrieve difference between power generation and total load

The total PLOAD is in channel # 4.

2020-08-19 01:30:40 -0500 answered a question Dynamic unbalance fault

Yes, any fault impedance is given in pu and a solid fault is entered with XL-G = 0.

The pu data system is described in manual "program Application Guide, Volume 1, Chapter 3.

2020-08-19 01:04:23 -0500 commented answer Initial conditions, snp and rstr for dynamic simulations

Check the dynamic models that have STATEs with initial conditions suspect.

2020-08-18 07:06:35 -0500 answered a question Retrieve difference between power generation and total load

Use channels for "Subsystem Power Totals" and select "All buses". Five channels are added:



3: TOTAL accelerating power



The total accelerating power is a good indicator of the deficit of turbine power in the system.

In a script, use psspy.chnval to retrieve the accelerating power during the simulation.

2020-08-13 04:31:18 -0500 commented answer Questions abour Coordinated Call Models

What's your email?

2020-08-12 11:24:51 -0500 answered a question how to transfer data when writing user-defined model

Local data can be transfered between models by using common blocks, i.e. model A and B can share and update the same variables.

2020-08-12 11:13:37 -0500 edited question Questions abour Coordinated Call Models

I have read POM about Coordinated Call Models. It says "coordinated call models, both those from the PSS®E Model Library as well as user-written models, must have their primary entry point name beginning with a character other than T.".

If I want to write a current injections model, how should I do?

1: Write a model begin with SUBROUTINE Modelname (MC, ISLOT) and call it in other model by writing:call Todelname (MC, ISLOT)?

or 2:

include 'comon4.ins'
local declarations
(mode 1,2...)
ENTRY Todelname (MC, ISLOT)
(mode 1,2...calculate current injection)
2020-08-12 11:07:27 -0500 answered a question Questions abour Coordinated Call Models

Alternative 2 is correct.

2020-08-12 03:03:10 -0500 answered a question Initial conditions, snp and rstr for dynamic simulations

It seems you have initial conditions suspect after first STRT. It is better to correct the issues causing initial conditions suspect. Is the saved case properly solved? Are any generator models hitting limits?

2020-08-11 15:59:09 -0500 commented question Qref of REPCA & REECA

Yes, you are correct. The second VAR is the Q reference for model REPCA. The output signal, also named Qref (!), seems to be hidden.

2020-08-11 15:08:12 -0500 answered a question Qref of REPCA & REECA

Qref is the second VAR of model REPCA1. Put the VAR into a channel.

2020-08-11 15:05:55 -0500 commented question Qref of REPCA & REECA

Qref is the second VAR of model REPCA1. Put the VAR into a channel.

2020-08-11 15:01:31 -0500 commented answer How to simulate 2 systems with different frequency in one file?

PSSE is using pu speed deviation, not Hz. At nominal speed (50 or 60 Hz) the pu speed deviation is zero. At under-frequency the pu speed deviation is negative.

2020-08-11 14:55:44 -0500 commented question Qref of REPCA & REECA

What do you mean with Qext? Model REPCA1 sends signals Pref and Qref to REECA1.

2020-08-11 00:55:50 -0500 commented answer Procedure to island a network

I assume the mismatch became too high for Newton/Raphson to solve, so you did it right in your case.

2020-08-07 09:34:22 -0500 commented answer How to simulate 2 systems with different frequency in one file?

In load flow the base frequency is only used for conversion of susceptance in pu system base to capacitance in microFarad in the GUI if line option is Ohms. So, there is no problem to have 50 Hz and 60 Hz systems in the same saved case.

2020-08-07 04:48:15 -0500 answered a question How to simulate 2 systems with different frequency in one file?

In PSSE all network data are stored in pu.

It is possible to have one saved case combining a 50 Hz and 60 Hz system, but that saved case will only have ONE base frequency; 50 or 60 Hz. You can't assign base frequency to individual buses.

Before reading the raw data for the second system you must change the frequency at the first line in the raw data file to the frequency of the first system. Also, change the IC code to 1. Note, there is no need to recalculate any branch or transformer data.

The line capacitance in the second system will be shown wrong (in spreadsheets and reports) if transmission line input option is set to Ohms, since the capacitance is calculated with wrong base frequency. However, the pu value is correct and the load flow is correct.

That means it is just to pretend that, for example, the 60 Hz system is a 50 Hz system and add it to the 50 Hz system.

2020-08-07 04:23:29 -0500 answered a question how do I list all buses from a Slider file

One way to list the buses is to export a bus location file.

From menu: File - Export - Bus locations...

2020-08-07 04:20:13 -0500 commented answer Procedure to island a network

There is no need for balancing the flow. Point 2 is not needed.

2020-08-07 04:17:49 -0500 commented answer Question on PSSE terminology

No, I mean what I wrote. You can ignore XTRAN and GENTAP if the step-up transformer is modelled in the saved case. If so, the transformer is already modelled and there is no need to enter the data in the machine record.