5 Theory and internal operation
85
•
U
Int
– minimum interrupt magnitude voltage is the lowers U
Rms(1/2)
value measured
on any channel during the interrupt.
•
The start time of a interrupt is time stamped with the time of the start of the
U
Rms(1/2)
of the channel that initiated the event, and the end time of the interrupt is
time stamped with the time of the end of the U
Rms(1/2)
that ended the event, as
defined by the threshold.
•
The duration of a voltage dip is the time difference between the start time and the
end time of the voltage dip.
5.1.12 Alarms
Generally alarm can be seen as an event on arbitrary quantity. Alarms are defined in
alarm table (see section 3.12.3 for alarm table setup). The basic measurement time
interval for: voltage, current, active, reactive and apparent power, harmonics and
unbalance alarms is 10-cycle time interval. Flicker alarms are evaluated according to
the flicker algorithm (Pst
1min
>1min, Pst > 10min, Plt > 10min).
Each alarm has attributes described in table bellow. Alarm occurs when 10-cycle
measured value on phases defined as
Phase,
cross
Threshold value
according to
defined
Trigger slope,
minimally for
Minimal duration
value.
Table 5.1: Alarm definition parameters
Quantity
•
Voltage
•
Current
•
Frequency
•
Active, reactive and apparent power
•
Harmonics
•
Unbalance
Flickers
Phase
L1, L2, L3, L12, L23, L31, All, Tot
Trigger slope
< - Fall , > - Rise
Threshold value
[Number]
Minimal duration
200ms ÷ 10min
Each captured alarm is described by following parameters
Table 5.2: Alarm signatures
Date
Date when selected alarm has occurred
Start
Alarm start time - when first value cross threshold.
Phase
Phase on which alarm occurred
Level
Minimal or maximal value in alarm
Duration
Alarm duration.
5.1.13 Data aggregation in RECORDING
Standard compliance: IEC 61000-4-30 Class S (Section 4.5.3)
Time aggregation period (IP) during recording is defined with parameter Interval: x min
in RECORDER menu.
