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Equivalent circuit: Represent external grid

asked Aug 15 '19

Dyn_Danmark gravatar image

Hi,

I have got SCC = 19000 MVA, I3F=34 kA and XO/X1=0.8 from a DSO. How to I calculate Impedances (R and X values) and set up the generator in PSS/E?

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I would calculate this as follows: Xth = X1 = MVAbase/MVAsc = 100/19000 = 0.00526 p.u. X0 = 0.8X1 = 0.8(0.00526) = 0.004208 p.u. Now, Xsorce = 0.00526 X0 = 0.004208

lmcqueen gravatar imagelmcqueen (Aug 19 '19)

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answered Aug 16 '19

perolofl gravatar image

Enter a generator with MBASE=19000, XSORCE=1 and Zero-X=0.8. The other short circuit reactances shall remain their default value, 1 pu. This generator will supply 19000 MVA short circuit power.

The bus base voltage must be 322.6 kV in order to get a three phase fault current of 34 kA. 322.6kV * 34kA * 1.73 = 19000 MVA!

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@perolofl Your information was very useful, in the case of using GENCLS what values ​​would be in Rsource and P, P max and Pmin, in addition to Q, Qmax and Qmin. Thanks for your help

Cris_Mx gravatar imageCris_Mx (Sep 29 '1)

Set Rsource to the wanted R/X ratio of the short circuit power. Set Pgen and Vscheduled to the wanted power and voltage at bus. An alternative is to fix Q by setting Qmax=Qmin.

perolofl gravatar imageperolofl (Sep 30 '1)

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Asked: Aug 15 '19

Seen: 1,152 times

Last updated: Aug 16 '19