5.6.3 Circuit breaker wear
The circuit breaker wear function is used for monitoring the circuit breaker's lifetime and its
maintenance needs caused by interrupting currents and mechanical wear. The function uses the circuit
breaker's manufacturer-supplied data for the breaker operating cycles in relation to the interrupted
current magnitudes.
Figure. 5.6.3 - 203. Example of the circuit breaker interrupting life operations.
The function is triggered from the circuit breaker's "Open" command output and it monitors the three-
phase current values in both the tripping moment and the normal breaker opening moment. The
maximum value of interrupting life operations for each phase is calculated from these currents. The
value is cumulatively deducted from the starting operations starting value. The user can set up two
separate alarm levels, which are activated when the value of interrupting life operations is below the
setting limit. The "Trip contact" setting defines the output that triggers the current monitoring at the
breaker's "Open" command.
The inputs for the function are the following:
• setting parameters
• binary output signals
• measured and pre-processed current magnitudes.
The function's outputs are ALARM 1 and ALARM 2 signals which can be used for direct I/O controlling
and user logic programming. The function generates general time-stamped ON/OFF events to the
common event buffer from each of the output signals. The time stamp resolution is 1 ms. The function
also provides a resettable cumulative counter for the "Open" operations as well as the ALARM 1 and
ALARM 2 events. The function can also monitor the operations left for each phase.
The following figure presents a simplified function block diagram of the circuit breaker wear function.
A
AQ
Q-M257
-M257
Instruction manual
Version: 2.07
© Arcteq Relays Ltd
IM00021
381
Summary of Contents for AQ-M257
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