ABB RELION 620 Series Technical Manual page 1005

1MRS757644 F
620 series
Technical Manual
Table 993: Live dead mode of operation under which switching can be carried out
Live dead mode
Both Dead
Live L, Dead B
Dead L, Live B
Dead Bus, L Any
Dead L, Bus Any
One Live, Dead
Not Both Live
When the energizing direction corresponds to the settings, the situation has to be
constant for a time set with the Energizing time setting before the circuit breaker
closing is permitted. The purpose of this time delay is to ensure that the dead side
remains de-energized and also that the situation is not caused by a temporary
interference. If the conditions do not persist for a specified operation time, the timer
is reset and the procedure is restarted when the conditions allow. The circuit breaker
closing is not permitted if the measured voltage on the live side is greater than the set
value of Max energizing V.
The measured energized state is available as a monitored data value ENERG_STATE
and as four function outputs LLDB (live line / dead bus), LLLB (live line / live bus),
DLLB (dead line / live bus) and DLDB (dead line / dead bus), of which only one can be
active at a time. It is also possible that the measured energized state indicates
"Unknown" if at least one of the measured voltages is between the limits set with the
dead and live setting parameters.
Synchro check
The Synchro check function measures the difference between the line voltage and bus
voltage. The function permits the closing of the circuit breaker when certain
conditions are simultaneously fulfilled.
• The measured line and bus voltages are higher than the set values of Live bus
value and Live line value (ENERG_STATE equals to "Both Live").
• The measured bus and line frequency are both within the range of 95 to 105
percent of the value of f
• The measured voltages for the line and bus are less than the set value of Max
energizing V.
In case Syncro check mode is set to "Syncronous", the additional conditions must be
fulfilled.
Description
Both line and bus de-energized
Bus de-energized and line energized
Line de-energized and bus energized
Both line and bus de-energized or bus de-
energized and line energized
Both line and bus de-energized or line de-
energized and bus energized
Bus de-energized and line energized or line de-
energized and bus energized
Both line and bus de-energized or bus de-
energized and line energized or line de-energized
and bus energized
.
n
Section 9
Control functions
999