ABB RELION REX640, Техническое руководство, Страница: 1115 / 1960

CB_CLOSED
signal. The
CB_CLOSED
signal is True when the CB position
is closed.
Under current detector
The Under current detector module can be enabled by setting
Enable under current
to “Enable” and disabled by setting it to “Disable”. The Under current detector
module is also disabled when
CB_CLOSED
is FALSE, that is, when circuit breaker is
open.
The fundamental frequency component of phase currents is compared to the
setting
Start value Un Cur. If all the three-phase currents are below the setting Start
value Un Cur, the Under current detector module enables the Timer 3 module.
Timer 3
Once activated, the Timer 3 module activates the
ST_UN_I
output. The operation is
based on DT characteristics. When the operation timer has reached the value of
Un
Cur delay time, the
OPR_UN_I
output is activated.
If the undercurrent situation disappears, the operation timer is reset. The
ST_DUR_UN_I
output indicates the percentage ratio of the undercurrent start
situation and the set operation time in the Timer 3 module and is available in the
monitored data view.
The
OPR_UN_I
output is of pulse type and remains TRUE for 150 ms. After that,
ST_DUR_UN_I
and
OPR_UN_I
are deactivated and
ST_DUR_UN_I
is reset.
If the circuit breaker closed status signal is not detected, the constant
value TRUE has to be connected to
CB_CLOSED
input to enable the
undercurrent detector.
If the circuit breaker status signal is not connected to
CB_CLOSED
input,
the
OPR_UN_I
output is activated even if the circuit breaker is open and
undercurrent is detected.
Inhibit reclose
When the output
OPR_UN_I
becomes active or when the
CB_CLOSED
state changes
from TRUE to FALSE, that is, when circuit breaker opens, the reclosing inhibition
module activates output
BLK_CLOSE
.
If Enable under current is set to “Disable”, the reclosing inhibition
operation is based purely on the
CB_CLOSED
input.
When the relay powers up after a reboot or software reset, or if the Operation of
COLPTOC function is switched from off to on, the
BLK_CLOSE
output is activated
defined by the
Reclose inhibit time, regardless the Reclose inhibit mode.
The behavior of the
BLK_CLOSE
output depends on
Reclose inhibit mode. If Reclose
inhibit mode is set to “Lockout”, the
BLK_CLOSE
output needs to be reset manually
from the clearing menu parameter COLPTOC inhibit recl. If Reclose inhibit mode is
set to “Non-latched”, the
BLK_CLOSE
output resets after the set Reclose inhibit time
has elapsed.
Blocking logic
There are three operation modes in the blocking function. The operation modes
are controlled by the
BLOCK
input and the global setting Configuration > System >
1MRS759142 F Protection functions
REX640
Technical Manual
1115