Duration Measurement - ABB RELION REX640 Technical Manual

1MRS759142 C
10.3.5.4
REX640
Technical Manual
Consequently, only one event detection and recording of the same variation type can
take place for one voltage variation, so the longest indicated variation of each
variation type is detected. Furthermore, it is possible that another instantaneous dip
event replaces the one already indicated if the magnitude again undershoots Voltage
dip set 1 for the set time after the first detection and the signal magnitude or time
requirement is again fulfilled. Another possibility is that if the time condition is not
fulfilled for an instantaneous dip detection but the signal rises above Voltage dip set 1,
the already elapsed time is included in the momentary dip timer. Especially the
interruption time is included in the dip time. If the signal does not exceed Voltage dip
set 2 before the timer VVa dip time 2 has elapsed when the momentary dip timer is also
started after the magnitude undershooting Voltage dip set 2, the momentary dip event
instead is detected. Consequently, the same dip occurrence with a changing variation
depth can result in several dip event indications but only one detection. For example,
if the magnitude has undershot Voltage dip set 1 but remained above Voltage Intr set
for a shorter time than the value of VVa dip time 1 but the signal rises between Voltage
dip set 1 and Voltage dip set 2 so that the total duration of the dip activation is longer
than VVa dip time 2 and the maximum time is not overshot, this is detected as a
momentary dip even though a short instantaneous dip period has been included. In
text, the terms "deeper" and "higher" are used for referring to dip or interruption.
Although examples are given for dip events, the same rules can be applied to the swell
and interruption functionality too. For swell indication, "deeper" means that the signal
rises even more and "higher" means that the signal magnitude becomes lower
respectively.
The adjustable voltage thresholds adhere to the relationships:
VVa dip time 1 ≤ VVa dip time 2 ≤ VVa dip time 3.
VVa swell time 1 ≤ VVa swell time 2 ≤ VVa swell time 3.
VVa Int time 1 ≤ VVa Int time 2 ≤ VVa Int time 3.
There is a validation functionality built-in function that checks the relationship
adherence so that if VVa x time 1 is set higher than VVa x time 2 or VVa x time 3, VVa
x time 2 and VVa x time 3 are set equal to the new VVa x time 1. If VVa x time 2 is set
higher than VVa x time 3, VVa x time 3 is set to the new VVa x time 2. If VVa x time 2 is
set lower than VVa x time 1, the entered VVa x time 2 is rejected. If VVa x time 3 is set
lower than VVa x time 2, the entered VVa x time 3 is rejected.

Duration measurement

The duration of each voltage phase corresponds to the period during which the
measured TRMS values remain above (swell) or below (dip, interruption) the
corresponding limit.
Besides the three limit settings for the variation types dip and swell, there is also a
specific duration setting for each limit setting. For interruption, there is only one limit
setting common for the three duration settings. The maximum duration setting is
common for all variation types.
Power quality measurement functions
Section 10
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