ABB Relion 620 Series - Page 831

Table 801: Options for dead line detection
Automatic SOTF Ini Description
DLD disabled The dead line detection function is disabled. This operation
mode must be applied when voltage transformers are loca-
ted on the bus side of the circuit breaker.
Voltage The dead line detection function is enabled and based solely
on the undervoltage condition. A dead line condition is de-
clared, if all the phase voltages are below the Voltage dead
Lin Val 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 con-
dition is signalled to the SOTF control after the delay defined
with the Dead line time setting.
Current The dead line detection function is enabled and based sole-
ly on the undercurrent condition. A dead line condition is
declared, if all the phase currents are below the Current dead
Lin Val 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 condi-
tion is signalled to the SOTF control after delay defined with
the Dead line time setting.
Current & Voltage The dead line detection function is enabled and based on un-
dercurrent and undervoltage condition. A dead line condition
is declared, if all the phase currents are below the Current
dead Lin Val setting and simultaneously all phase voltages
are below the Voltage dead Lin Val setting. The dead line is
detected if the dead line condition is declared and simulta-
neously no fault is detected by the START and START_DLYD
inputs. The dead line condition is signalled to the SOTF con-
trol after delay defined with the Dead line time setting.
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.
Dead line detection should be used only when the voltage transformers
are located on the line side of the circuit breaker.
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
1MRS757644 H
Protection related functions
620 series
Technical Manual
831