How do I calculate the field forcing per unit value for my generator model in EasyPower?

The “Field Forcing” value is the voltage represented in per unit form that will generate the final steady state short circuit current of the generator.

The calculation used is: E(field forcing)(pu) = I Final (pu) * X d (pu)

The generator data sheet gives us a Current Decrement plot and values for this generator.

From this we see the final steady state short circuit current is 5,695 A.

To get the per unit, we divide by the generator rated current of 1878.8 A

I Final (pu) = 5,695/1878.8 = 3.03 pu

Xd = 3.4966 (from an early page of the data sheet)

From the calculation above: E(field forcing)(pu) = I Final (pu) * X d (pu)

So E(field forcing)(pu) = 3.03 * 3.4966 = 10.6 pu

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