
82 Shipboard Electrical Power Systems
E x V P
f
= + = = =6351 1575 2 7089 7 089
6 351
2 2
( ) .
.
max
kV,and
×
77 089
2
22 51
.
.= MW
Power delivered by generator, P =
1
/
3
× 30 MVA × 1.0 pf = 10 MW/phase
The power angle is then derived from Equation (4.5):
P
gen
= 10 = 22.51 sinδ, which gives δ = 26.4°
Example 4.4
A 3-phase, Y-connected synchronous generator is rated 10 MVA, 11 kV. Its
resistance is negligible, and the synchronous reactance is 1.5 Ω per phase.
Determine the generator voltage E
g
when delivering rated MVA at 0.85 power
factor lagging.
SOLUTION
E
g
is an alternative symbol used in some books and national standards for the
field excitation