When the phase angle criterion is used, the DIRECTION output indicates on which
operating sector the negative or residual power is measured.
Low-level blocking
For a reliable operation, signal levels should be greater than the minimum level. If
they are not greater than the minimum level, Timer is blocked.
In the "Neg. seq. volt." polarization selection using the
Pol quantity
setting, if the
amplitude of the negative-sequence current is greater than the
Min operate current
value and the negative-sequence voltage amplitude is greater than the
Min operate
voltage
value, the Enable signal is sent to Timer.
In the "Zero seq. volt." polarization selection using
Pol quantity
, if the amplitude
of the residual current is greater than the
Min operate current
value and residual
voltage amplitude is greater than the
Min operate voltage
value, the Enable signal is
sent to Timer.
Timer
Once activated, the internal operating timer is started. The Timer characteristic
is according to DT. When Timer has reached the value of
Release delay time
,
the RELEASE output is activated. If a drop-off situation happens, that is, if the
operating current moves out of the operating sector or signal amplitudes drop
below the minimum levels, before
Release delay time
is exceeded, the Timer reset
state is activated. If the drop-off continues for more than
Reset delay time
, Timer is
deactivated.
Blocking logic
The binary input BLOCK can be used to block the function. The activation of the
BLOCK input deactivates RELEASE output and resets Timer.
5.15.6 Application
The neutral power directional element function DNZSRDIR improves the possibility
to obtain selective function of the overcurrent protection in meshed networks.
DNZSRDIR is used to block or release other overcurrent protection functions.
5.15.7 Signals
5.15.7.1 DNZSRDIR Input signals
Table 1223: DNZSRDIR Input signals
Name
Type Default Description
I3P SIGNAL - Three-phase currents
IRES SIGNAL - Residual current
U3P SIGNAL - Three-phase voltages
URES SIGNAL - Residual voltage
Table continues on the next page
Protection related functions 1MRS759142 F
1292 REX640
Technical Manual
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