Page 583 - Handbook of Electrical Engineering

576 HANDBOOK OF ELECTRICAL ENGINEERING

Hence the terminal voltage of the generator V gn is:-

E o Z ogn
V gn =
Z gn
= 0.9691 − j0.0359 pu, which has a magnitude of 0.9697 pu.

t) Starting conditions

The motor starter is closed. Repeat the procedure as for s) but use the motor starting impedance,
and using the suffix ‘s’ for starting.

The parallel impedance of the running motor is Z mn :-

R ms = 3.8244 and X ms = j0.9875 pu

The total load resistance on the SWBD is R ls where:-

R o × R ms
R ls = = 1.4095 pu
R o + R ms
The total load reactance on the SWBD is X ls where:-

X o × X ms
X ls = = 0.7991 pu
X o + X ms

The series equivalent resistance is R ogs :-

0.7991 × 0.7991 × 1.4095
R ogs = = 0.3429 pu
2
0.7991 + 1.4095 2
The series equivalent reactance is X ogs :-

0.7991 × 1.4095 × 1.4095
X ogs = = 0.6047 pu
0.7991 + 1.4095 2
2
The total impedance seen by the generator emf E o is Z gs :-

Z gs = R g + R ogs + j(X g + X ogs )
= 0.02 + 0.3429 + j(0.25 + 0.6047)
= 0.3629 + j0.8547 pu

The current in the generator I gs is:-

(1.0686 − j0.1072)(0.3629 − j0.8547)
I gns = E o =
0.8622
= 0.5560 − j1.0142 pu