also the
DIPST
outputs are activated. When the TRMS voltage magnitude remains
between
Voltage dip set 2 and Voltage dip set 1 for a period longer than VVa dip
time 2 (shorter time than VVa dip time 3), a momentary dip event is detected.
Furthermore, if the signal magnitude stays between the limits longer than
VVa dip
time 3 (shorter time than VVa Dur max), a temporary dip event is detected. If the
voltage remains below
Voltage dip set 1 for a period longer than VVa dip time 1 but
a shorter time than
VVa dip time 2, an instantaneous dip event is detected.
For an event detection, the
OPERATE
output is always activated for one task cycle.
The corresponding counter and only one of them (INSTDIPCNT, MOMDIPCNT or
TEMPDIPCNT) is increased by one. If the dip limit undershooting duration is shorter
than
VVa dip time 1, VVa swell time 1 or VVa Int time 1, the event is not detected
at all, and if the duration is longer than
VVa Dur Max, MAXDURDIPCNT is increased
by one but no event detection resulting in the activation of the
OPERATE
output
and recording data update takes place. These counters are available through the
monitored data view on the LHMI or through tools via communications. There are
no phase-segregated counters but all the variation detections are registered to
a common time/magnitude-classified counter type. Consequently, a simultaneous
multiphase event, that is, the variation-type event detection time moment is exactly
the same for two or more phases, is counted only once also for single-phase power
systems.
Voltage dip set 1
Voltage dip set 2
Voltage dip set 3
Voltage
xUref
Time (ms)
0
0
VVa Dur Max
VVa dip time 3
VVa dip time 1
VVa dip time 2
1.00
Instantaneous
dip
Temporary
dip
Momentary
dip
Maximum duration
dip
Figure 577: Voltage dip operational regions
, the corresponding limits regarding the swell operation are provided
with the inherent magnitude limit order difference. The swell functionality principle
is the same as for dips, but the different limits for the signal magnitude and times
and the inherent operating zone change (here,
Voltage swell set x > 1.0 xUn) are
applied.
1MRS757644 H
Power quality measurement functions
620 series
Technical Manual
1093
