MI 2883 Energy Master
Theory and internal operation
148
Table 5.6: EN 50160 standard LV limits (continuous phenomena)
Supply voltage
phenomenon
Acceptable
limits
Meas.
Interval
Monitoring
Period
Acceptance
Percentage
Power frequency
49.5 ÷ 50.5 Hz
47
.0 ÷ 52.0 Hz
10 s
1 Week
99,5%
100%
Supply voltage variations,
U
Nom
230V
± 10%
10 min
1 Week
95%
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 5.7
10 min
1 Week
95%
Mains signalling
See Figure 5.17
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 5.7: 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
)
