Basler Electric BE1-11t - Manual (Page 178)

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edit this value at the front panel. To view the breaker status using BESTCOMSPlus, use the Metering
Explorer to open the Control, Breaker Control Switch tree branch.
The breaker operations counter can be monitored to give an alarm when the value exceeds a threshold.
See Breaker Alarms in this chapter for more information about this feature.
Breaker duty monitoring is discussed in the following paragraphs.
Breaker Duty Monitoring
When the breaker opens, the current interrupted in each pole of the circuit breaker is accumulated by the
breaker duty monitor. Breaker opening is defined by the breaker status monitoring function (Breaker
Status). Figure 122 illustrates breaker status during a fault and protective trip. Table 62 serves as a
legend for the call-outs of Figure 122.
Each time the breaker trips, the breaker duty monitor updates two sets of registers for each pole of the
breaker. In the Accumulated I Duty registers, the breaker duty monitor adds the measured current in
primary amperes. In the Accumulated I
2 Duty registers, the function adds the measured current in
primary amperes squared. The user selects which of the two sets of duty registers are reported and
monitored when setting up the breaker duty monitor.
Even though duty register values are calculated and stored in primary amperes or primary amperes-
squared, the duty value is reported as a percent of maximum. The user sets the value that the BE1-11t
will use for 100 percent duty (D
MAX
). The value set for maximum duty is used directly for reporting the
accumulated I Duty. The square of the value set for maximum duty is used for reporting the accumulated
I
2 duty.
Since the true measure of contact wear includes a factor for arcing time (t), an assumed arcing time for
the breaker should be included when choosing the setting for 100 percent interruption duty (D
MAX
).
When testing the BE1-11t by injecting currents into the BE1-11t, the values in the duty registers should be
read and recorded prior to the start of testing. Once testing is complete and the BE1-11t is returned to
service, the registers should be reset to the original pre-test values. A block accumulation logic input can
be used when testing so that simulated breaker duty is not added to the duty registers. The Block logic
input of the breaker duty function is an OR logic term (e.g., IN1 or OUT5) which blocks the breaker
monitoring logic when true (1). Block is set to zero to disable blocking. When breaker monitoring is
blocked (logic expression equals 1), breaker duty is not accumulated.
Breaker Monitoring BE1-11t