How to Change Generator Reactance Value to %

[PDF] Calculating generator reactances

Yes! It does mean that the Direct Axis Synchronous Reactance is 192.26%, which means that the intenal voltage drop within the generator windings with rated load at rated power factor, will be 192.26% of the rated terminal voltage, which also means that the EMF generated by the generator will be 292.26% of the rated termial voltage.

The generator reactance is 1.9226 per unit means the calculated per unit value of the generator is 1.9226 with the base value of the generator's rated KVA and rated voltage.

For example, the generator is assumed 5 MVA, 11KV, 3 phase. For this case, the base KVA is 5000 and base KV is 11 (L-L).

For this system,

The base impedance (Zbase) = (Base KV)² x 1000 / Base KVA

= (11x11x1000) / 5000 = 24.2 ohm

The actual reactance of the generator

= base impedance (Zbase) x per unit value = 24.2 x 1.9226 = 46.53 ohm

Hope it helps.

- MS