Section 14.5: Performance of a Round-Rotor Synchronous Generator cont.
Ia = |Ia|/q where |Ia| = 2.5 MVA/(Ö3´6.6KV) = 218.7 A. and q = -cos-1(0.8) » -36.87° so that KVL yields:
E = Vt + ZsIa = 3811 V. + 10.4/89.6°W ´ 218.7/-36.87° A.
Calculate the % voltage regulation for a three-phase wye-connected 2.5 MVA, 6.6 KV synchronous generator operating at rated KVA load, 0.8 lagging power factor. The synchronous impedance is Zs = Ra +jXs = (0.071 + j10.4)W (N.B.: 6.6 KV/Ö3 » 3811 V.)