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Is it possible to change generator and load values in dynamic simulation?

asked 2015-12-05 00:49:19 -0500

Enigma gravatar image

for example in IEEE 39 dynamic simulation G1=100MW at t=0s load in bus 3 is 75MW and then G1=150MW at t=0.5s load in bus 3 changes to 75MW and then G1 return to 100MW at t=1s load in bus 3 changes to 20MW print the dynamic curves for G1

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answered 2016-09-26 15:29:26 -0500

perolofl gravatar image

The output from the generator is determined by the turbine power (PMECH). The variable PMECH(MC) may be updated by code in CONEC subroutine during a simulation but that needs some Fortran code and a compiler.

Instead I propose that governor model IEESGO is used for update of PMECH as you wish during the simulation. With the parameters I have chosen below the model will instantaneously update PMECH after changes to GREF. The script is adapted to savnw test case, but the concept can be used for any case.'savnw.sav')
psspy.conl(0,1,1,[0,0],[ 80.0,0.0, 20.0, 80.0])
psspy.conl(0,1,2,[0,0],[ 80.0,0.0, 20.0, 80.0])
psspy.conl(0,1,3,[0,0],[ 80.0,0.0, 20.0, 80.0])
ibus = 3011
gid = '1'
dp = 50.  # MW change for generator
ierr, mbase = psspy.macdat(ibus, gid, 'MBASE')
# add dummy governor without droop and time constants

ierr = psspy.strt(0, 'test1.out'), 0.5,0,1,0)
psspy.increment_gref(ibus,gid, dp/mbase), 1.0,0,1,0)
psspy.increment_gref(ibus,gid,-dp/mbase), 2.0,0,1,0)

The following Figure shows how PMECH for the studied generator is updated during the simulation. image description

PMECH is always in pu generator base (Mbase=1000). The turbine power is here temporarily increased with 50 MW (50/1000=0.05 pu) at t=0.5 s and reset again at t=1 s.

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This is helpful. Thank you

Dao Vu gravatar imageDao Vu ( 2019-01-25 01:34:42 -0500 )edit

answered 2015-12-07 00:47:00 -0500

SqFKYo gravatar image

You can use machine_chng_2 to change machine data, and load_chng_4 for load changes during dynamic simulations for PSS/E 33 at least.

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Thanks ,but I have used function machine_chng_2, it could only change the power flow data. It could not make any changes in the dynamic simultaion

Enigma gravatar imageEnigma ( 2015-12-18 00:46:17 -0500 )edit

Did you get some error? Are you using the PSS/E 33? I have used `load_chng_4` successfully myself in my own dynamic script.

SqFKYo gravatar imageSqFKYo ( 2015-12-18 00:51:02 -0500 )edit

I use PSSE 33 too,and the function load_chng_4 is useful but it could only change load data.I mean the function machine_chng_2 could not change the machine output power in dynamic simulation

Enigma gravatar imageEnigma ( 2015-12-18 01:57:34 -0500 )edit

Thanks for the clarification. I'm not 100% sure, but this sounds like the dynamics data controls the power output, and you'd have to use the change_var or such methods. In order to do that, you'd need to first check which dynamics models your system is using and consult MODELS.pdf.

SqFKYo gravatar imageSqFKYo ( 2015-12-18 02:08:06 -0500 )edit

No,I just simply use psspy.dyre_new and psspy.dynamics_solution_param_2 and psspy.strt and I could not copy my hold code here because the 300 characters limit, could you please leave your email so I could send my code to you. Thanks

Enigma gravatar imageEnigma ( 2015-12-18 02:23:15 -0500 )edit

answered 2017-04-21 11:09:49 -0500


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answered 2015-12-25 09:26:37 -0500

martincho8002 gravatar image

May be you can make a workaround by creating an artificial generator that is not actually there in reality but will serve you to make changes in load? If the simplifications of this artificial generator are o.k. with you may be it is a good compromise. You will disconnect this generator at times when the load needs to increase and you will increase the governor reference (Pmech power) mechanical power of this generator when your load needs to decrease.

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Asked: 2015-12-05 00:49:19 -0500

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Last updated: Apr 21 '17