Live dead mode
Description
One Live, Dead
Bus de-energized and line energized or line
de-energized and bus energized
Not Both Live
Both line and bus de-energized or bus de-
energized and line energized or line de-ener-
gized and bus energized
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
valueand 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
n
.
• 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.
• In the synchronous mode, the closing is attempted so that the phase difference
at closing is close to zero.
• The synchronous mode is only possible when the frequency slip is below 0.1
percent of the value of f
n
.
• The voltage difference must not exceed the 1 percent of the value of U
n
.
In case
Syncro check mode is set to “Asyncronous”, the additional conditions must
be fulfilled.
• The measured difference of the voltages is less than the set value of
Difference
voltage.
• The measured difference of the phase angles is less than the set value of
Difference angle.
• The measured difference in frequency is less than the set value of
Frequency
difference.
• The estimated breaker closing angle is decided to be less than the set value of
Difference angle.
1MRS757644 H
Control functions
620 series
Technical Manual
1001
