Woodward MRM4, Manual

Page: 402 / 460

Supervision
Supervision
CBF- Circuit Breaker Failure [50BF]
Available elements:
CBF
Principle – General Use
The breaker failure (BF) protection is used to provide backup protection in the event that a breaker fails to oper-
ate properly during fault clearing. A breaker failure condition is recognized if current is still flowing through the
breaker after tripping or opening breaker commands have been issued for a specified time. The User can select
different trigger modes. In addition, up to three additional trigger events (trip commands) can be assigned from
all the protection modules.
Trigger Modes
There are three trigger modes for the breaker failure available. In addition, there are three assignable trigger
inputs available.
•
All Trips : All trip signals that are assigned to this breaker (within the breaker manager) will start the BF
module.
•
Current Trips : All current trips that are assigned to this breaker (within the breaker manager) will start
the BF module.
•
External Trips : All external trips that are assigned to this breaker (within the breaker manager) will start
the BF module.
In addition, the User can also select none (e.g.: if the User intends to use one of the three additional assignable
trigger inputs).
Those trips can exclusively start the breaker failures that are assigned
within the breaker manager to the breaker that is to be supervised.
Select the winding side from which the measured currents should be taken
in case this protective device is a transformer differential protection.
Page 402 EN MRM4 01/11