ABB RELION REX640 Technical Manual page 1268

Section 7
Condition monitoring functions
1262
manufacturer. The remaining life is decremented at least with one when the circuit
breaker is opened.
The operation of the remaining life of the circuit breaker subfunction can be described
with a module diagram. All the modules in the diagram are explained in the next
sections.
GUID-017CE531-FE3B-4D0D-B0C6-A2F235318AA0 V1 EN
Figure 691: Functional module diagram for estimating the life of the circuit
breaker
Circuit breaker life estimator
The circuit breaker life estimator module calculates the remaining life of the circuit
breaker. If the tripping current is less than the rated operating current set with the
Rated Op current setting, the remaining operation of the breaker reduces by one
operation. If the tripping current is more than the rated fault current set with the Rated
fault current setting, the possible operations are zero. The remaining life of the
tripping current in between these two values is calculated based on the trip curve given
by the manufacturer. The Op number rated and Op number fault parameters set the
number of operations the breaker can perform at the rated current and at the rated fault
current, respectively.
The remaining life is calculated separately for all three phases and it is available as a
monitored data value CB_LIFE_A (_B,_C). The values can be cleared by setting
the parameter CB wear values in the clear menu from WHMI or LHMI.
Clearing CB wear values also resets the operation counter.
Alarm limit check
When the remaining life of any phase drops below the Life alarm level threshold
setting, the corresponding circuit breaker life alarm CB_LIFE_ALM is activated.
It is possible to deactivate the CB_LIFE_ALM alarm signal by activating the binary
input BLOCK. The old circuit breaker operation counter value can be taken into use by
writing the value to the Initial CB Rmn life parameter and resetting the value via the
clear menu from WHMI or LHMI.
1MRS759142 C
REX640
Technical Manual