Error and suspect during initialization

TonyWong
1 ●3 ●5 ●4

Anyone knows what does the following initialization error message means and how to fix it? And why sometimes after a few iterations or further down the dynamic simulation steps, the initialization would disappear?

*****ZPSS2A AT BUS:20691 MACH 1  :
 Machine in Synch Comp mode - KS1 set to zero 

*****ZPSS2A AT BUS:20692 MACH 2  :
 Machine in Synch Comp mode - KS1 set to zero 

*****WSTAB4 AT BUS:44281 MACH 1  :
 Machine in Synch Comp mode - Kx set to zero 


 ERROR: PELEC outside LUT range
 MODE = 1
 VREF(I) = 0.9861
 STATEs =    0.986   0.986   1.039   3.842   3.842   1.614   3.788   3.788

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Are the generators in synchronous generator mode, i.e. Pgen=0?

perolofl (Jun 27 '19)

Yes, the generator output is very close to zero, but not the reactive power output (around 2MVAR from 42.5MVA base machine). What do you reckon the problem is?

TonyWong (Jun 30 '19)

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answered Jul 2 '19

TonyWong
1 ●3 ●5 ●4

updated Jul 3 '19

perolofl

3452 ●1 ●9 ●20

Hi patrickrossiter, I do have initialization suspect. Here I only paste part of the message related to switched shunt. As you suggested, I looked up generator with terminal voltage being 0.9861pu and found two. But neither of their P/Q is beyond limits, however, one generator has Pgen=Pmax=Pmin=0.

INITIAL CONDITIONS SUSPECT:
     I   DSTATE(I)    STATE(I)     MODEL             STATE     BUS# X-- NAME --X BASKV  ID
   203   0.22517       1.0232      GENSAL             K       20691 2GPS_G1     11.500  1
   208   0.20950       1.0042      GENSAL             K       20692 2GPS_G2     11.500  2
   213   0.46492E-02 -0.14608      CSVCQA             K       20750 2SYW_S1     330.00  1
  4564   0.12042E-03  0.62448E-02  UN6UEL             K+1     20023 2EPS_G3     23.000  3
  4918   0.38564E-01   3.0661      UN6EXC             K+7     20021 2EPS_G1     23.000  1
  4930   0.12042E-03  0.62448E-02  UN6EXC             K+1     20023 2EPS_G3     23.000  3
  5339   0.10780E-03  0.14448E-02  ZMSSE2             K+3     30331 3MUR_G11    17.000  11
  5353   0.12899E-03  0.14302E-02  ZMSSE2             K+3     30332 3MUR_G12    17.000  12
  5367   0.11199E-03  0.14251E-02  ZMSSE2             K+3     30333 3MUR_G13    17.000  13
  5381   0.91735E-04  0.14428E-02  ZMSSE2             K+3     30334 3MUR_G14    17.000  14
ODE 4
ODE 4
ODE 4
ODE 4
NO ACTIVE TABLE MODEL CALL FOR SWITCHED SHUNT AT BUS  20405 [2BUK_G5     11.000]
NO ACTIVE TABLE MODEL CALL FOR SWITCHED SHUNT AT BUS  20640 [2GAD_G1     11.000]

.......

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answered Jul 1 '19

patrickrossiter

1 ●5 ●7 ●8

I think that the error you are seeing is unrelated to the PSS messages you are getting. LUT generally stands for lookup table. I would suggest looking at UEL models and seeing whether any machines are outside their reactive limits, or active power greater than PMAX.

I would start looking at the swing bus, and then any machines you have added to the case (or other machines in the area) which have a terminal voltage of 0.9861 pu. Did you get any suspect initial conditions?

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Comments

It may be an exciter model. Check machines with Efd=3.842 or 3.788.

perolofl (Jul 1 '19)

Hi perolofl, I followed patrickrossiter and your thoughts, and found one generator with terminal voltage being 0.9861pu. After initialization, the one VARS of the generator exciter model is 3.788 exactly. Still do not understand why this is a problem. And why I found this value in VARs list?

TonyWong (Jul 2 '19)

And this generator has a Min exciter model 'DC2UEL', and there is no VARs value after initialization. Can you please explain a little bit about what does those numbers after 'STATEs = ' in the original script mean? where can i find those values in my initialized model?

TonyWong (Jul 2 '19)

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answered Jun 29 '19

perolofl

3452 ●1 ●9 ●20

Do you have any documentation of the stabiliser user written models?

It looks like the Pelec signal of the PSS is blocked at low electric active power (Pgen=0 in load flow).

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Hi perolofl, what does LUT shorts for? How do you know it has something to do with PSS? I have absolutely no idea what should I look for?

TonyWong (Jun 30 '19)

LUT seems to be a power range where the PSS is active. The power is below the range. The models are PSS models!

perolofl (Jun 30 '19)

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Error and suspect during initialization

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