ABB RELION REX640, Техническое руководство, Страница: 1225 / 1960

non-directional distance zone or overcurrent stage, is required for fault indication.
The
START
and
START_DLYD
inputs are available for the purpose.
• The
START
input has no delay. Thus, a switch-onto-fault situation is immediately
signalled to SOTF control.
•
START_DLYD
is used when an additional delay is required to start the signal. The
switch-onto-fault situation is signalled to the SOTF control after the set
Operate
delay time.
Dead-line detector
The dead line detection should be used only when the voltage
transformers are located on the line side of the circuit breaker.
The
Automatic SOTF Ini setting is used to configure the internal dead line detection
function.
Table 1167: 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 sole-
ly on the undervoltage condition. A dead line condition is
declared, 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
1MRS759142 F Protection related functions
REX640
Technical Manual
1225