
152 Shipboard Electrical Power Systems
or otherwise), then the ampere and ohm bases are indirectly defined from the
following relations:
In 1-phase system, I
kVA
V
base
base
base
=
1000
A/phase
Z
V
I
V
kVA
kV
MVA
base
base
base
base
base
base
ba
= = =
2 2
1000
sse
Ω/phase (6.8)
In large high-voltage, 3-phase systems, it is customary to state 3-phase kVA and
line-to-line voltage in kV
LL
, but the power system analysis is still done on a per phase
(line-to-neutral) basis, where
In 3-phase system, I
kVA
kV
base
ph base
LLbase
=
3
3
.
A/phase
Z
kV
kVA
kV
MVA
base
LLbase
ph base
LL base
ph
= =
1000
2
3
2
3.
.
..base
Ω/phase (6.9)
The values of base volts, base amperes, and base ...