ABB RELION REX640 Technical Manual page 1134

Section 5
Protection related functions
1128
Table 1060: Options for dead line detection
Automatic SOTF Ini
DLD disabled
Voltage
Current
Current & Voltage
SOTF detection
The purpose of this module is to detect the switch onto fault situation based on the
current and voltage measurements. If the voltage, in any of the phases, is below the
Voltage dead Lin Val setting and simultaneously the current in the same phase exceeds
the Current dead Lin Val setting, the SOTF situation is signalled to SOTF control
module after the set Cur voltage Det time.
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
Description
The dead line detection function is disabled. This
operation mode must be applied when voltage
transformers are located on the bus side of the
circuit breaker.
The dead line detection function is enabled and
based solely on the undervoltage condition. A
dead line condition is declared, if all the phase
Voltage dead Lin Val
voltages are below the
setting. The dead line is detected if the dead line
condition is declared and simultaneously no fault
is detected by the START and START_DLYD
inputs . The dead line condition is signalled to the
SOTF control after the delay defined with the
line time setting.
The dead line detection function is enabled and
based solely on the undercurrent condition. A
dead line condition is declared, if all the phase
Current dead Lin Val
currents are below the
setting. The dead line is detected if the dead line
condition is declared and simultaneously no fault
is detected by the START and START_DLYD
inputs. The dead line condition is signalled to the
SOTF control after delay defined with the
line time setting.
The dead line detection function is enabled and
based on undercurrent and undervoltage
condition. A dead line condition is declared, if all
the phase currents are below the
Val setting and simultaneously all phase voltages
Voltage dead Lin Val setting. The
are below the
dead line is detected if the dead line condition is
declared and simultaneously no fault is detected
by the START and START_DLYD inputs. The dead
line condition is signalled to the SOTF control after
Dead line time setting.
delay defined with the
1MRS759142 C
Dead
Dead
Current dead Lin
REX640
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