Linzhi's profile - activity

Thank you very much! Jose. I will carefully study the tools you recommended. If possible, I would like to ask for your help here in further uses. Thanks again!

Hi, all. AC power flow calculation can be unsolvable due to lose of the operating point.

I want to identify the bus where to shed load to take back the operation point, and try to leverage the eigenvalues of Jacobian matrix. However, I cannot find the way to use them. What python API to retrieve the eigenvalues?

I looked up the forum and found only this answer: psspy.org/psse-help-forum/question/1487/how-to-do-cascading-failure-simulation/. The user Rounak said to calculate Load Shift Factor based on the entries of the LSF matrix, what are they?

Thank you!

I noticed your gmail address on your google share.

I just typed in "import psspy", but got "No Module name psspy". Besides, Jose I have some other more urgent questions that I am looking forward to guidance, could I send you emails for help?

Hello, why cannot I import psspy in python after pip install pywin32?

Hello, I am wondering the Load Shift Factor and the LSF matrix you said. I have no idea how to find, calculate and retrieve them by python code. Could you tell me some details? Thank you!

Thank you! I used to think of this way which was kinda troublesome.

Since there is always no answer, this thought is impossible? So sad...

Hello,

PSSE offers OPF calculation, but I cannot find the solution output other wise result report in progress window or report window. What if I want to read the values in the solution after OPF calculation in python? I looked it up in the API instruction but find no functions that can return solution values to variants.

Thank you!

I have found out some other errors in my codes. So it is probably not the numpy that my problem stems from.

But the problem with matplotlib in psse32 exactly exists.

Hello,

Numpy library is a very popular library for python users in math and science. But psse32 only support python 2.5.1, in which the up-to-date numpy cannot be compatible.

So I looked up for a proper numpy library and found numpy 1.5.1, the release of which said it can be used for python 2.5, but did not precisely given the x of 2.5.x.

My simulation runs well in most of the time, but sometimes the psse32 may result in no responding, leaving me unaware of where the error is. I checked all my while loops to ensure no endless loops exist, so I can only guess that the problem is due to the incompatibility between psse32 and the numpy library.

Why did I think in this way? Because I used to install another python library matplotlib in my python25, when calling functions in matplotlib using psse32, the simulation could be very unstable, sometimes a plot could be worked out, otherwise psse32 resulted in no responding.

Did anybody install numpy for your python25 for psse32?

Your question is not clear for me. What is the end line of a dyr file? If it was edit the contents in it, it would just be the operation of file read&write work in matlab, which should be easy.

Thanks a lot. Your advice is instructive and easy to handle. I will keep it in mind to avoid changing generation within dynamic simulation, while some witching events like load shedding must happen in power system operation.

I've found the answer by @perolofl in https://psspy.org/psse-help-forum/que...

As said in it, the electric power is determined by the turbine power. As an example does @perolofl introduce the IEESGOV model, the reference of which is P0, the reference can be changed by applying the API increment-gref. However, other turbine models does not follow the same setting, if I use increment-gref, for some models the GREF is speed instead of P0.

Another option according to @perolofl is to count on Fortran code and a compiler, which I cannot manage.

I am trying to change the power output of generators step by step, to get close to the rotor angle stability limit. Is there any alternatives for me?

Thanks a lot! I've downloaded it, and luckily I also learnt other files in your share, really precious!

Thank you! My edition is 32, so the menu is different from yours. The chapter title helps, I've got your idea.

Moreover, I will replace the UFLS models by my code for more specific and flexible study, which even user-written models cannot behave. BTW, why is the precedence order necessary?

Thank you very much! You're really a master. I noticed that by applying models in different level and with a wildcard (’*’) identifier or not. Sadly the conflicts are not wanted and both UFLS and UVLS are needed in simulation. So, temporally I chose to write the function UVLS myself.

Hello,

I'm working with a simulation focusing on load shedding methods, counting on load relay models, LVSHBL and LDSHAL.

Firstly, I found that only on load relay model can be applied on a single load, but I can configure both at the same bus by setting specific load id for one of it while setting no load id with a asterisk for the other. I don't know whether that would work because I haven't run it yet.

Secondly, this is what I met, I configured LVSHBL for each load bus and a LDSHAL model for All, but only LVSHBLs work even the frequency decreased beyond the shed point of LDSHAL. I delete all LVSHBL models and run again, then UFLS occurs. At last I exchanged the models, LDSHBL for every bus and LVSHAL for All loads, then simulation shows only LDSHBL works.

So, does it mean that only local load relay models can work, then the models set on the level of Area, Zone, All loads will be disabled?

Thank you for any help.

@perolofl was right.

more detailedly, the starting indexes of VAR, CON, ICON, STATE can be returned by API like mdlind, lmodind, etc., and the index for the data you want is based on the model documentary.

The simple solution is good enough for us new learners. But there is no Program Operation Guide in the documentaries, the most similar part might be Program Operation Manual? And the is no Chapter 21.9 either.

@oppossumX was quit right

I only met such situation when more than 2 PSSE are running Newton Raphson method simultaneously, and other processes of PSSE crashes but one. I don't know why, but seemingly the access of some stuff about YMATRIX data is limited.

Your demo code with the link "https://drive.google.com/drive/folders/0B7uS9L2Woq7YzYzcGhXT2VQYXc" is invalid. Has it been deleted?

@bad_hand was wrong. The units for generator speeds are pu, the Hz value can be worked out by timing the base frequency, for example 50Hz. If the speed deviation is -0.05, the frequency deviation should be -2.5Hz.