MI 2892 Power Master
Theory and internal operation
163
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-400
-300
-200
-100
0
100
200
300
400
time (s)
voltage(V)
Figure 5.10: Voltage fluctuation
Flickers are measured in accordance with standard IEC 61000-4-15. Standard defines the transform
function based on a 230 V / 60 W and 120 V / 60 W lamp-eye-brain chain response. That function is a
base for flicker meter implementation and is presented on figure below.
P
st1min
– is a short flicker estimation based on 1-minute interval. It is calculated to give quick preview of
10 minutes short term flicker.
P
st
– 10 minutes, short term flicker is calculated according to IEC 61000-4-15
P
lt
– 2 hours, long term flicker is calculated according to the following equation:
3
1
3
N
Pst
P
N
i
i
ltp
p: 1,2,3
(65)
5.1.11
Voltage and current unbalance
Standard compliance: IEC 61000-4-30 Class A (Section 5.7)
The supply voltage unbalance is evaluated using the method of symmetrical components. In addition to
the positive sequence component U
+
, under unbalanced conditions there also exists negative sequence
component U
-
and zero sequence component U
0
. These quantities are calculated according to the
following equations:
)
(
3
1
3
2
2
1
U
a
U
a
U
U
)
(
3
1
3
2
1
0
U
U
U
U
,
)
(
3
1
3
2
2
1
U
a
U
a
U
U
,
(66)
where
0
120
1
3
2
1
2
1
j
e
j
a
.
