Initial conditions, snp and rstr for dynamic simulations

asked 2020-08-11 21:09:45 -0600

IndiraX
27 ●8 ●10 ●14

updated 2020-08-11 21:41:39 -0600

Hi guys,

I run a simulation in steady-state conditions but frequency changes slightly at the begining of the simulation, then it goes steady-state. https://drive.google.com/drive/folders/1RKPD_ED-xdk6kirFo1x2oLDEJrwucP8q?usp=sharing

I tried to save the snp at t=300 s with this code:

psspy.strt(0, outputfile) 
psspy.dynamics_solution_param_2(intgar1 = 5000, realar1 = 0.25, realar3 = 0.001)
psspy.strt(0, outputfile) # 2nd start is needed to get initial conditions to SS
sim_time = 300.0 # simulation
psspy.run(0, sim_time, 9999,1000,1000)
psspy.progress_output(1,"",[0,0]) # turn it on
psspy.save('post2simulation.sav')
psspy.snap(sfile = 'post2simulation.snp')

Then, I used post2simulation.snp as ini2simulation.snp and load it at the begining of my next simulation with this code:

psspy.case(casefile + '.sav')
psspy.rstr(sfile = 'ini2simulation.snp')

But I still have that stage of transition at the begining of my simulation.

Do you think this is related to my save case, dyr or snp?

Thanks in advance!!

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answered 2020-08-12 03:03:10 -0600

perolofl

3322 ●1 ●8 ●18

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?

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Hi there! Thanks for your comments. I didn't have any generator out of limits, and I think save case was OK, because I tried to keep the swing generator output as similar as possible.

IndiraX ( 2020-08-18 20:16:54 -0600 )edit

What I did was to go back to the original case, and try to disconect generators but this time trying to reduce inertia equally from the north and south parts of the network, thus I did not have any problem with ss conditions runing dyn simulations.

IndiraX ( 2020-08-18 20:18:44 -0600 )edit

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

perolofl ( 2020-08-19 01:04:23 -0600 )edit

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answered 2020-08-11 22:13:28 -0600

jconto
2701 ●10 ●30 ●41

In dynamics, the case and the snp file work as a pair, synchronized in time.

At t=300 you save the case and snp file. For the new simulation you use the case at t=0 with a snp file at t=300. Try using the case at t=300 with the snp file at t=300 as the starting files for the new simulation.

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Hi, I have also tried taking the sav and snp files and use them for the new simulation but PSS/E gets stuck, and in the progress window is showed: NUMBER OF ELEMENTS RESTORED: CONS ... Day_Light.out Messages for api LTAP Ckt "3" from bus 46130 ... not found (002067)

IndiraX ( 2020-08-11 22:40:34 -0600 )edit

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Initial conditions, snp and rstr for dynamic simulations

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