21/07/2010
16
MRAR 01/96 C
Alarm AR Blocked Relay (49, 47, 51)
Operation:
When a blocking condition is present.
Release:
When the blocking signal has been cancelled.
Self Supervision Alarm Relay (50, 48, 52)
Operation:
A system hardware/software error.
Release:
When fault has been removed.
5.5 Blocking and Cancellation of Blocking
5.5.1 Blocking
The AR Relay is blocked under the following conditions:
•
•
•
•
A circuit breaker defect was detected during reclosing.
•
The external blocking input was activated.
•
The AR cycle was terminated without success.
•
The circuit breaker energy is not sufficient during a switch on attempt (after first attempt) see also
paragraph 5.3.9.
•
The synchronous condition does not exist (can be discounted if auxiliary supply connected to
terminal 23)
•
The preset number of reclosings for the maintenance lockout has been reached.
•
When the reclosing shot is set to zero, the MRAR can also be blocked at site.
5.5.2 Cancellation of Blocking
The maintenance lockout is cancelled by resetting the AR value (No) to zero. All other blocking inputs
can only be cancelled through the external reset input, terminal 25.
