ABB REL650 series, Applications Manual

Page: 460 / 516

Directional Coef
B
A
I
I
f
r
=












= −
log
log
. 2 2609
A070794 V2 EN
(Equation 177)
I
r
Rated operating current = 630 A
I
f
Rated fault current = 16 kA
A Op number rated = 30000
B Op number fault = 20
Calculation for estimating the remaining life
The equation shows that there are 30,000 possible operations at the rated operating current
of 630 A and 20 operations at the rated fault current 16 kA. Therefore, if the tripping
current is 10 kA, one operation at 10 kA is equivalent to 30,000/500=60 operations at the
rated current. It is also assumed that prior to this tripping, the remaining life of the circuit
breaker is 15,000 operations. Therefore, after one operation of 10 kA, the remaining life
of the circuit breaker is 15,000-60=14,940 at the rated operating current.
Spring charging time indication
For normal circuit breaker operation, the circuit breaker spring should be charged within
a specified time. Therefore, detecting long spring charging time indicates the time for
circuit breaker maintenance. The last value of the spring charging time can be given as a
service value.
Gas pressure supervision
The gas pressure supervision monitors the gas pressure inside the arc chamber. When the
pressure becomes too low compared to the required value, the circuit breaker operations
are locked. A binary input is available based on the pressure levels in the function, and
alarms are generated based on these inputs.
Section 14
1MRK 506 334-UUS A
Monitoring
454
Application manual