ABB RELION REX640 Technical Manual page 1226

Protection related functions
exceeds the
control module after the set
SOTF control
The SOTF control module needs to be activated before the operation is possible
in the switch-onto-fault situation. There are two ways to activate the SOTF control
module.
• By CB_CL_CMD (circuit breaker closing command).
• By the dead line condition received from the dead line detection module.
When the CB_CL_CMD input is activated or the dead line condition is detected, the
SOTF control module becomes active. The reset timer is started when CB_CL_CMD
is inactivated or the dead line condition disappears. Thus, the module becomes
inactive after the set
When the SOTF control module is active, the
operation criteria for the detection of a switch-onto-fault condition. The detection
can be based on the external start signals from the distance or overcurrent
functions, on the measured internal voltage and current levels, or on both.
Table 1168: Options for SOTF detection
Operation mode
Start
Current & Voltage
Both
The OPERATE output can be blocked by activating the BLOCK input.
5.8.6 Application
The operation of CVPSOF is generally based on the non-directional distance zone or
the non-directional overcurrent stage. When the feeder-side voltage transformers
are used for providing the polarization quantity for the distance or directional
overcurrent protection, the use of non-directional impedance or current based
protection for starting CVPSOF secures a fast switch-onto-fault tripping in the
close-in three-phase short circuits. The non-directional protection provides a fast
fault clearance when the protection is used for energizing a bus from the feeder
with a short circuit fault in it. Other protection functions, like time delayed zero-
sequence overcurrent functions, can be connected to CVPSOF to increase the
dependability of the scheme. The other main advantage of using CVPSOF is that it
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Current dead Lin Val setting, the SOTF situation is signalled to SOTF
Cur voltage Det time .
Dead line detection should be used only when the voltage transformers
are located on the line side of the circuit breaker.
SOTF reset time is exceeded.
Description
The
from the trigger module. This indicates that the breaker is
closed onto fault.
The
from the SOTF detection module. This indicates that the
breaker is closed onto fault. This operation mode can be
used, for example, if the non-directional distance zone is not
available.
The
from the trigger or SOTF detection modules. This indicates
that the breaker is closed onto fault.
Operation mode setting defines the
output is activated immediately after a signal
OPERATE
output is activated immediately after a signal
OPERATE
output is activated immediately after a signal
OPERATE
1MRS759142 F
REX640
Technical Manual