The
IPOW_ALM
and
IPOW_LO
outputs can be blocked by activating the binary input
BLOCK
.
7.1.5.6
Remaining life of circuit breaker
Every time the breaker operates, the life of the circuit breaker reduces due to
wearing. The wearing in the breaker depends on the tripping current, and the
remaining life of the breaker is estimated from the circuit breaker trip curve
provided by the 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.
Figure 780: Functional module diagram for estimating the life of the circuit breaker
CB life estimator
CB life estimator module calculates the remaining life of the circuit breaker. 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. If the
tripping current is lower 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 higher than the rated fault current set with the
Rated fault
current setting, the remaining operation of the breaker reduces by Op number rated
divided by
Op number fault. The remaining life reduction of the tripping current
in between these two values is calculated based on the trip curve given by the
manufacturer.
Directional Coef
Op number fault
Op number rated
=
log
log
g
Rated fault current
Rated Op current
(Equation 319)
Remaining life reduction
Rated Op current
-Dire
=
I
fault
c
ctional Coef
(Equation 320)
1MRS759142 F
Condition monitoring functions
REX640
Technical Manual
1367