Directional Coef
B
A
I
I
f
r
=
= −
log
log
.2 2609
A070794 V2 EN (Equation 81)
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
Figure 341 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
30,000/60=500 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
15,000-500=14,500 at the rated operating current.
Spring-charged indication
For normal operation of the circuit breaker, the circuit breaker spring should be
charged within a specified time. Therefore, detecting long spring-charging time
indicates that it is time for the circuit breaker maintenance. The last value of the
spring-charging time can be used 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.
7.1.6 Signals
Table 525: SSCBR Input signals
Name
Type Default Description
I_A SIGNAL 0 Phase A current
I_B SIGNAL 0 Phase B current
I_C SIGNAL 0 Phase C current
BLOCK BOOLEAN 0=False Block input status
POSOPEN BOOLEAN 0=False Signal for open position of apparatus from I/O
POSCLOSE BOOLEAN 0=False Signal for closeposition of apparatus from I/O
Table continues on next page
1YHT530004D05 D Section 7
Condition monitoring functions
615 series 619
Technical Manual
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