Hioki CM3286 - Page 95

89
Equations
(5) Unbalanced 3-phase/4-wire power measurement
Unbalanced 3-phase/4-wire
active power
P
(UB3P4W)
[W]
P
1
+
P
2
+
P
3
• The symbol
P
1
represents the active power of the
phase voltage
U
1
and the wire current
I
1
.
• The symbol
P
2
represents the active power of the
phase voltage
U
2
and the wire current
I
2
.
• The symbol
P
3
represents the active power of the
phase voltage
U
3
and the wire current
I
3
.
• The active power
P
has no sign during consumption
and a negative sign during generation.
Unbalanced 3-phase/4-wire
apparent power
S
(UB3P4W)
[VA]
S
1
+
S
2
+
S
3
• The symbol
S
1
represents the apparent power of the
phase voltage
U
1
and the wire current
I
1
.
• The symbol
S
2
represents the apparent power of the
phase voltage
U
2
and the wire current
I
2
.
• The symbol
S
3
represents the apparent power of the
phase voltage
U
3
and the wire current
I
3
.
• Due to the effects of measurement error
,
S
=|
P
| is
used when
S
<|
P
|.
Unbalanced 3-phase/4-wire
reactive power
Q
(UB3P4W)
[var]
Q
1
+
Q
2
+
Q
3
• The symbol
Q
1
represents the reactive power of the
phase voltage
U
1
and the wire current
I
1
.
• The symbol
Q
2
represents the reactive power of the
phase voltage
U
2
and the wire current
I
2
.
• The symbol
Q
3
represents the reactive power of the
phase voltage
U
3
and the wire current
I
3
.
• Due to the effects of measurement error
,
Q
=0 is
used when
S
<|
P
|.