Sbase = Pbase in p.u values? 1

[AusLee]

Hello,

I am reading something about per unit values and the text seems ok:

Zpu = Z(actual)/Zbase, Ipu = I(actual)/Ibase

but then they say: P(base) = S(base)

Shouldn't P(base)=S(base)*cos(Phi)?

(the material is from an ebook written using Mathcad).

Thanks.

 

[electricpete]

Cos(phi) is unitless. There is no need for two different bases for P and S.

If it makes you feel better, choose Phi =0, cos(Phi)=1.

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[AusLee]

Thanks, i do feel better