Figure 415 shows voltage dip operational regions. In Figure 414, only one voltage
dip/swell/Int set is drawn, whereas in this figure there are three sub-limits for the
dip operation. When Voltage dip set 3 is undershot, the corresponding ST_x and
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 MaxVVa dip time 3VVa dip time 1 VVa dip time 2
1.00
Instantaneous
dip
Temporary
dip
Momentary
dip
Maximum duration
dip
GUID-0D3F6D81-F905-4D8D-A579-836EF7BB6773 V1 EN
Figure 415: Voltage dip operational regions
In Figure 416, 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.
Section 10 1YHT530004D05 D
Power quality measurement functions
776 615 series
Technical Manual
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