MI 2892 Power Master
Theory and internal operation
180
230V
+10%
-15%
100%
Flicker severity Plt
Plt ≤ 1
2 h
1 Week
95%
Voltage unbalance u-
0 ÷ 2 %,
occasionally 3%
10 min
1 Week
95%
Total harm. distortion, THD
U
8%
10 min
1 Week
95%
Harmonic Voltages, Uh
n
See Table 5.9
10 min
1 Week
95%
Mains signalling
See Figure 5.29
2 s
1 Day
99%
5.2.1
Power frequency
The nominal frequency of the supply voltage shall be 50 Hz, for systems with synchronous connection to
an interconnected system. Under normal operating conditions the mean value of the fundamental
frequency measured over 10 s shall be within a range of:
50 Hz ± 1 % (49,5 Hz .. 50,5 Hz) during 99,5 % of a year;
50 Hz + 4 % / - 6 % (i.e. 47 Hz .. 52 Hz) during 100 % of the time.
5.2.2
Supply voltage variations
Under normal operating conditions, during each period of one week 95 % of the 10 min mean U
Rms
values of the supply voltage shall be within the range of U
Nom
± 10 %, and all U
Rms
values of the supply
voltage shall be within the range of U
Nom
+ 10 % / - 15 %.
5.2.3
Supply voltage unbalance
Under normal operating conditions, during each period of one week, 95 % of the 10 min mean RMS
values of the negative phase sequence component (fundamental) of the supply voltage shall be within
the range 0 % to 2 % of the positive phase sequence component (fundamental). In some areas with
partly single phase or two-phase connected network users’ installations, unbalances up to about 3 % at
three-phase supply terminals occur.
5.2.4
THD voltage and harmonics
Under normal operating conditions, during each period of one week, 95 % of the 10 min mean values of
each individual harmonic voltage shall be less or equal to the value given in table below.
Moreover, THD
U
values of the supply voltage (including all harmonics up to the order 40) shall be less
than or equal to 8 %.
Table 5.9: Values of individual harmonic voltages at the supply
Odd harmonics
Even harmonics
Not Multiples of 3
Multiples of 3
Order h
Relative
voltage (U
N
)
Order h
Relative voltage
(U
N
)
Order h
Relative
voltage (U
N
)
5
6,0 %
3
5,0 %
2
2,0 %
7
5,0 %
9
1,5 %
4
1,0 %
11
3,5 %
15
0,5 %
6..24
0,5 %
13
3,0 %
21
0,5 %
17
2,0 %
19
1,5 %
23
1,5 %
25
1,5 %
