How to get pu reactance values from % reactance for synchronous generators

[Islander1]

Hi All,

I'm trying to model a synchronous generator in SKM PTW using synchronous generator datasheet. I need to put saturated reactances values in pu, however the datasheet provides me reactances in percentage values. Does anyone know how to convert % values into pu values?
Here is my values in %:

Any help would be appreciated.

Thanks,

 

[xnuke]

Divide by 100.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[crshears]

What xnuke said.

Per cent = for every one hundred
Per unit = for every one

The easiest way to calculate this is to move the decimal point in the percentage value two places to the left; the result is the per unit value.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[Islander1]

Thanks Crshears and Xnuke for the answers.
I was not sure whether that percentage is of actual value or of pu value. SO it is the percentage of pu value.

 

[wroggent]

It is a percentage of the "base impedance" i.e. X_pu = X_actual/Z_base

 

[waross]

% Reactance is a component of % Impedance.
The full name of % Impedance is;
"Percent Impedance Voltage."
The Impedance voltage is the voltage required to drive rated current through a shorted secondary winding.
Example:
If it takes 3 Volts applied to a 100 Volt winding to drive rated current to drive through a shorted secondary then the PU value is
3 Volts / 100 Volts = 0.03 PU impedance.
3 Volts / 100 Volts x 100 = 3% impedance (voltage)

It is a percentage of the "base impedance" i.e. X_pu = X_actual/Z_base

Uhh maybe add in base KVA, Pythagoras and a factor of 100?

Bill
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