Master And Slave Scheme - ABB RED615 Technical Manual

Section 9
Control functions
9.4.3.3
9.4.3.4
694

Master and slave scheme

With the cooperation between the AR units in the same IED or between IEDs,
sequential reclosings of two breakers at a line end in a 1½-breaker, double breaker
or ring-bus arrangement can be achieved. One unit is defined as a master and it
executes the reclosing first. If the reclosing is successful and no trip takes place, the
second unit, that is the slave, is released to complete the reclose shot. With
persistent faults, the breaker reclosing is limited to the first breaker.
A070877 V1 EN
Figure 373: Master and slave scheme
If the AR unit is defined as a master by setting its terminal priority to high:
• The unit activates the CMD_WAIT output to the low priority slave unit
whenever a shot is in progress, a reclosing is unsuccessful or the
BLK_RCLM_T input is active
• The CMD_WAIT output is reset one second after the reclose command is given
or if the sequence is unsuccessful when the reclaim time elapses.
If the AR unit is defined as a slave by setting its terminal priority to low:
• The unit waits until the master releases the BLK_RECL_T input (the
CMD_WAIT output in the master). Only after this signal has been deactivated,
the reclose time for the slave unit can be started.
• The slave unit is set to a lockout state if the BLK_RECL_T input is not
released within the time defined by the Max wait time setting , which follows
the initiation of an auto-reclose shot.
If the terminal priority of the AR unit is set to "none", the AR unit skips all these
actions.
Thermal overload blocking
An alarm or start signal from the thermal overload protection (T1PTTR) can be
routed to the input BLK_THERM to block and hold the reclose sequence. The
BLK_THERM signal does not affect the starting of the sequence. When the reclose
time has elapsed and the BLK_THERM input is active, the shot is not ready until the
BLK_THERM input deactivates. Should the BLK_THERM input remain active
longer than the time set by the setting Max block time, the AR function goes to lockout.
If the BLK_THERM input is activated when the auto wait timer is running, the auto
wait timer is reset and the timer restarted when the BLK_THERM input deactivates.
1YHT530004D05 D
615 series
Technical Manual