P54x/EN OP/La4 Operation
(OP) 5-190
MiCOM P543, P544, P545 & P546
OP
5.6.6.2 Auto-reclose enable (P544/P546)
The auto-reclose enable logic is shown in AR Figure 5 (logic diagram supplement).
A maste
r enable/disable signal provides overall control of the auto-reclose function for the
circuit breakers. If the Auto-reclose setting cell in the CONFIGURATION column of the
menu is set to enabled the auto-recloser can be brought into service with other commands
(described below) providing further control.
In the figure, the auto-recloser is enabled when the AR In Service DDB (1385) is driven
high. To achieve this, as well as enabling the Auto-reclose setting cell in the
CONFIGURATION column of the menu, conditions 1 and 2 below must be met:-
1. Auto-reclose must be enabled for at least one of the circuit breakers (CB1/CB2). This is
achieved by enabling DDB input AR Enable CB1 (1609) for CB1 and/or AR Enable CB2
(1605) for CB2. Both these DDBs signals default to high if not mapped in the PSL so, if
they are not mapped, this part of the logic will always be satisfied.
2. Auto-reclosing needs to be enabled from an opto input mapped to the AR Enable DDB
(1384), or one of the following 3 conditions must be met :-
A menu command from the HMI Auto-reclose Mode cell in the CB CONTROL column
of the menu is used to bring the auto-recloser into service, or,
For a P544/P546 having IEC 60870-5-103 communications, a standardised enable
auto-reclose command is received via the communications link, or,
The auto-recloser is brought into service by the pulsing of the AR Pulse On DDB (1382).
The result of the logic above is the auto-reclose status. This can be seen in the data cell AR
Status in the CB CONTROL column of the menu, and will be either In Service or Out of
Service.
5.6.6.3 Leader & follower circuit breaker selection (P54
4/P546)
The leader and follower circuit breaker selection logic is shown in AR Figure 6 (logic diagram
sup
plement).
The method of selecting the preferred leader and follower circuit breakers is determined by
the menu setting Leader Select By, which can be set to Leader by Menu, Leader by Opto
or Leader by Ctrl.
If Leader Select By: is set to Leader by Menu, a further setting, Select Leader:, becomes
visible and is used to select the preferred leader circuit breaker by setting Select Leader:
either to Sel Leader CB1 or Sel Leader CB2.
If Leader Select By: is set to Leader by Opto, the preferred leader circuit breaker is
determined by the status of the input DDB (1408): CB2 Lead. If the input DDB (1408) CB2
Lead is low, then preferred leader circuit breaker is CB1. If DDB CB2 Lead is high then it
selects CB2 as the preferred leader.
If Leader Select By: is set to Leader by Control, then the preferred leader circuit breaker is
determined by the user control command CTRL CB2 Lead cell found under the CB
CONTROL column in the relay menu. If the command applied is Reset CB2 Lead, CB1 is
selected as the preferred leader. Applying Set CB2 Lead command selects CB2 as the
preferred leader.
If Num CBs is set to Both CB1 &CB2, either CB1 or CB2 can be selected as leader. If the
setting Num CBs is set to CB1 Only, CB1 is selected as leader. Similarly, CB2 is selected
as leader if the setting Num CBs is set to CB2 Only.
Provided that the circuit breaker is available for auto-reclose (i.e. the circuit breaker is: in
service, not locked out, and enabled for auto-reclosing {refer sections 5.6.6.2 and 5.6.6.4}),
the “preferred” leader circuit
breaker will be the “active” leading circuit breaker in the auto-
reclose cycle.
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