Transformer modelling for switching transient

[Adam1980]

Dear all,

I am doing a transient study for which the transofmer data from the manufacturer is not easy to provide.

Concerning that issue i have two questions:
1- are there any recommended values of the transformer capacitances (transformer is 40 MVA YYN0 132/33 kV). I will be calculating switching transients (slow front) but may also consider fast fronts for re-strikes. Would considering/neglecting the capacitances affect the calculations?
There are some proposed values from not so official sources but with quite a large range (IEEE industrial applications society magazine).
2- would the phase shift of the transformer affect the calculations? I have an inverter transformer with a phase shift of 10°. This is not available from the model.

Thank you.

 

[FPelec]

Adam,
as regards the influence of transformer capacitance on switching transients, it depends on where the circuit breaker is: if you are simulating transformer switching-off transient the effect of its capacitance is not negligible; the same applies if you are studing a phenomenon that could involve the transformer itself (i.e. transformer-terminated lines or energization of lines through a transformer). If you are performing a switching transient study on a large network, the effect is much less important.
As regards phase shift it could be more important for harmonic studies rather than fast transients ones

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