ABB RELION REX640, Техническое руководство, Страница: 1371 / 1960

Figure 783: Trip Curves for a typical 12 kV, 630 A, 16 kA vacuum interrupter
Nr the number of closing-opening operations allowed for the circuit breaker
Ia the current at the time of tripping of the circuit breaker
Calculation for estimating the remaining life
Figure 783
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.
1MRS759142 F Condition monitoring functions
REX640
Technical Manual
1371