MI 2792 PowerQ4 Plus
Theory and internal operation
119
User can choose to perform single or continuous inrush loggings. If continuous inrush
logging is performed, PowerQ4 Plus will automatically initialize next inrush logging upon
completion of the previous one. Two
initial
consecutive inrush loggings can be
performed without “dead time” in between. The third inrush logging will be initialized
only when the first one is being completely saved to the instrument data memory. Dead
time is proportional to record duration and number of selected recording signals, and
usually takes few seconds.
5.2 EN 50160 Standard Overview
EN 50160 standard defines, describes and specifies the main characteristics of the
voltage at a network user’s supply terminals in public low voltage and medium voltage
distribution networks under normal operating conditions. This standard describe the
limits or values within which the voltage characteristics can be expected to remain over
the whole of the public distribution network and do not describe the average situation
usually experienced by an individual network user. An overview of EN 50160 limits are
presented on table bellow.
Table 5.5: EN 50160 standard overview
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%
230V ± 10%
95%
Supply voltage variations,
U
Nom
230V
+10%
-15%
10 min
1 Week
100%
Flicker severity Plt
Plt
≤
1
2 h
1 Week
95%
Voltage Dips (
≤
1min)
10 to 1000 times
(under 85% of
U
Nom
)
10 ms
1 Year
100%
Short Interruptions
(
≤
3min)
10 ÷ 100 times
(under 1% of U
Nom
)
10 ms
1 Year
100%
Accidental long interruptions
(> 3min)
10 ÷ 50 times
(under 1% of U
Nom
)
10 ms
1 Year
100%
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
10 min
1 Week
95%
Mains signalling
See Figure 5.15
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.
