Current unbalance ratio aunb, Capacitance calculation, Iumb – KYORITSU 6315 Instruction Manual User Manual
Page 141: Var 1 1 1 1, Kpf pf p c, Fpf pf v f p
Items to be calculated
KEW6315
- 139 -
KEW6315
Current unbalance ratio Aunb [%]
Displayed digit
5-digit
Display range
0.00% to100.00%
Wiring
3P3W, 3P4W
Equation
(
)
(
)
100
6
3
1
6
3
1
×
−
+
−
−
=
β
β
Iumb
(
)
2
2
31
2
23
2
12
4
31
4
23
4
12
A
A
A
A
A
A
+
+
+
+
=
β
* The 1st order components of harmonic current are used.
* For 3P4W system, phase voltages are converted to line voltages for
calculation.
A
12
= A
1
- A
2,
A
23
= A
2
- A
3,
A
31
= A
3
- A
1
Capacitance calculation
Displayed digit
4-digit, Unit: nF, µF, mF, kvar
Display range
0.000nF - 9999F, 0.000kvar - 9999kvar
Equation
[
]
var
1
1
1
1
2
arg
_
2
k
PF
PF
P
C
et
T
C
C
C
C
−
−
−
×
=
[ ]
F
PF
PF
V
f
P
et
T
C
C
C
C
µ
−
−
−
Ч
Ч
Ч
=
1
1
1
1
2
10
2
arg
_
2
2
9
π
C
c
: Capacitance needs for improvement
P
c
: Load power (active power)〔kW〕
f
: Frequency
V
c
: R.m.s. voltage
PF
c
: Measured PF
PF
c_Target
: New power factor (target)
c
: Measurement channel
1P2W-1 to 4
C
1
, C
2
, C
3
, C
4
, C
sum
=C
1
+C
2
+C
3
+C
4
1P3W(3P3W)-1
to 2
C
1
, C
2
, C
sum1
=C
1
+C
2
C
1
, C
2
, C
sum2
=C
3
+C
4
C
sum
=C
sum1
+ C
sum2
3P3W3A(3P4W)
C
1
, C
2
, C
3
, C
sum
=C
1
+C
2
+C
3