Siemens SIPROTEC 7UT613 series Manual page 180

2 Functions
Pickup, Trip
Figure 2-78 Logic diagram of the high-current stage I
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Two definite time stages are available for the earth current.
For the IE>> stage, the current measured at the assigned 1-phase current input is
compared with the setting value IE>>. Current above the pickup value is detected and
annunciated. When the delay time T IE>> has expired, tripping command is issued.
The reset value is approximately 95 % below the pickup value for currents above I
Lower values require a higher hysteresis in order to avoid intermittent pickup on cur-
rents near the pickup value (e.g. 20 % at 0.1 ·I
The following figure shows the logic diagram for the high-current stage IE>>.
The current detected at the assigned one-phase current measuring input is addition-
ally compared with setting value IE>. An annunciation is generated if the value is ex-
ceeded. If inrush restraint is used, a frequency analysis is performed first. If an inrush
condition is detected, pickup annunciation is suppressed and an inrush message is
output instead. If there is no inrush or if inrush restraint is disabled, a tripping
command will be output after expiration of delay time T IE>. If inrush restraint is
enabled and inrush current is detected, there will be no tripping. Nevertheless, an an-
nunciation is generated indicating that the time expired. The dropout value is roughly
equal to 95% of the pickup value for currents I > 0,3 · I
The Figure shows the logic diagram of the overcurrent stage IE>.
The pickup values for each of the stages IE> and IE>> and the delay times can be
set individually.
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>> for earth current (simplified)
E
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7UT613/63x Manual
C53000-G1176-C160-2
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