Signals - ABB RELION REX640 Technical Manual

1MRS759142 C
5.9.7
REX640
Technical Manual
If the fault is located on the adjacent feeder or bus within the reach of
the overreaching zone, the tripping and the AR initiation take place
during an external fault.
Setting guidelines
The Load current value setting must be set below the minimum three-phase load
current during the healthy state. A security factor of 0.5 is used:
Load current value = 0.5 ⋅ I
I minimum load current during normal operation conditions
minload
The loss of load function is released after Load release on time is elapsed and the load
current in all three phases is above the Load current value setting. If the current values
drop below the Load current value setting, the release condition stays activated until
the drop-out delay time has expired (the Load release off Tm setting). The value of
Load release off Tm is by default set to "0.3 s". The Load release on time setting is used
to increase the security of the loss of load function, for example, in the case of transient
inrush currents during the energizing of a power transformer. When there is no need
for delaying the release, the Load release on time is set to zero in applications.
The Minimum current setting is used to detect the loss of load condition in healthy
phases during the fault. The Minimum current setting is set to a value higher than the
maximum current flowing in the healthy phases during the fault when the breaker at
the remote end has been opened and the load flowing through has therefore been
disconnected. This current can be, for example, due to the charging current of the
phases or the load current of the tapped loads. The Minimum current setting value is
set below the Load current value setting. By default, the Minimum current setting
value is set to "0.05 pu".
The Minimum current time setting is used to provide the start delay for the loss of load
current detection to avoid an unwanted release of the function. The value of Minimum
current time is by default set to "0.2 s".

Signals

Table 1069: DSTPLAL Input signals
Name Type
I3P SIGNAL
BLOCK BOOLEAN
AR_READY BOOLEAN
CB_CL_CMD BOOLEAN
Table continues on next page
Protection related functions
minload
Default Description
- Three-phase currents
0=False Block signal for activating the blocking mode
0=False Autoreclosure ready, releases function used for
fast trip
0=False CB close command
Section 5
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