Alstom MiCOM P54 Series - 5.6.6.9 Dead time control (P544;P546); 5.6.6.10 Follower circuit breaker enable and time control (P544;P546)

P54x/EN OP/La4 Operation
(OP) 5-194 MiCOM P543, P544, P545 & P546
OP
and/or three phase reclosing is permitted for that circuit breaker. Dependent upon the
settings and trip performed, each circuit breaker can perform:-
 Single phase reclose as Leader (with or without follower);
 Single phase reclose as Follower (provided the leader is also selected to single phase
auto-reclose);
 Three phase reclose as Leader (with or without follower);
 Three phase reclose as Follower;
5.6.6.9 Dead time control (P544/P546)
The de
ad time control logic is shown in AR Figure 22, Figure 24, Figure 25 and Figure 26
(
logic diagram supplement).
Once an auto-reclose cycle has started, the conditions to enable the dead time to run are
determined by menu settings, circuit breaker status, protection status, the nature of the auto-
reclose cycle (single phase or three phase) and opto inputs from external sources.
Three settings are involved in controlling the dead time start :-
 DT Start by Prot
 3PDTStart WhenLD
 DTStart by CB Op.
The DT Start by Prot setting is always visible and has three options Protection Reset,
Protection Op, and Disable. These options set the basic conditions for starting the dead
time.
The ‘dead time started by protection operation’ condition can, optionally, be qualified by a
check that the line is dead.
The ‘dead time started by protection reset’ condition can, optionally, be qualified by a check,
that the circuit breaker is open, as well as by an optional check that the line is dead (note*).
If the DT Start by Prot is set to Disable, the circuit breaker must be open for the dead time
to start. This condition can, optionally be qualified by a check that the line is dead (note*).
The qualification to check that the ‘line is dead’ is provided by setting 3PDTStart WhenLD to
Enabled.
The qualification to check that the ‘circuit breaker is open’ is provided by setting DTStart by
CB Op to Enabled.
In a dual circuit breaker scheme (Num CBs set to Both CB1 & CB2) if the DTStart by CB
Op is set to enabled, both circuit breakers must be tripped to enable the dead time to start.
For a single phase auto-reclose cycle, the leader circuit breaker has to be tripped single
phase. For a three phase auto-reclose cycle, both circuit breakers have to be tripped three
phase.
Note*: This is only applicable when tripping/auto-reclose is three phase.
5.6.6.10 Follower circuit breaker enable and time control (P54
4/P546)
The follower circuit breaker control logic is shown in AR Figure 27, Figure 28 and Figure 29
(
logic diagram supplement).
When a leader/follower auto-reclose cycle is initiated, the conditions for the follower delay
period (Follower Time) to start are determined by the leader circuit breaker operation, the
follower circuit breaker status, the menu setting BF if LFail Cls (Block Follower reclose if
Leader CB Fails to close), and opto inputs from external sources. The basic condition to
start the follower delay is that the leader circuit breaker must have reclosed.