
22-21Power Measurement
Hence, the overall reactive power is
Q Q Q P P= + = − +
12 32 1 30 3 10
3
( ) ( )
(2
2
.60
)
22.2.3.8
T
hr
ee-Wattmeter Insertion
A three-wire, three-phase system can be measured by three wattmeters connected as in Figure 22.24.
e articial neutral point position does not aect the measurement; it is usually imposed by the imped-
ance
o
f
t
he
v
oltmeter
l
eads
o
f
t
he
w
attmeters
.
22
.2.3.9
Me
dium-Voltage,
Thr
ee-Wattmeter Insertion
Analogously
to th
e
sin
gle-phase
ca
se,
fo
r
me
dium-voltage
ci
rcuits,
th
e
th
ree-wattmeter
in
sertion
is
modied as in Figure 22.25.
22
.2.3.10
Me
thod Selection Guide
For
th
ree-wire
sy
stems,
th
e
o
w
ch
art
of Fi