MI 2892 Power Master
Theory and internal operation
179
t
U
Level
Allowed waveform area
(envelope)
Figure 5.27: Transients trigger detection (envelope)
Level trigger is activated if sampled voltage/current is greater than given limit.
t
U
Level
Figure 5.28: Transients trigger detection (envelope)
Note: Saving to the instrument data memory induces dead time between consecutive transient records.
Dead time is proportional to record duration, and in worst case for 50 sec long transient it will take 4
seconds, before new transient can be captured.
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 Low
voltage limits are presented on table below.
Table 5.8: 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%
