Flat Start Oscillations

Hello all,

I've been working with a dynamic case and just caught that the generators oscillate ever so slightly from "flat start." When I perform the simulation during flat start it seems that everything is fine, but the generators will experience a max 0.000004 P.U. deviation 100MVA base. These oscillations occur on generators that are outputting about 750 MW of power. I'm wondering if these intrinsic differences are due to PSS/e software's failure to capture such a resolution?

Thanks!

Lassettc

asked 2015-10-09 18:28:48 -0500

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What is the frequency of the oscillation? If it is fast, it could be numerical. If it is within ~5Hz, it could be damping issues with slightly incorrect initial conditions. What happens if you trip a load and bring it back (or any other dynamic pulse)?

Jacde

answered 2015-10-11 16:19:58 -0500

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I consider an acceptable flatstart for a real system when you get maximum deviations in the order of:

angle: 10e-1 or smaller

power, var (Q),: 10e-2 or smaller

voltage:10e-3 or smaller

Speed: 10e-3 or smaller

In your case, 4 x10e-6, is pretty small for power deviation.

2.9k

jconto

answered 2015-10-12 09:20:13 -0500

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Flat Start Oscillations edit

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