Basler Electric BE1-851 - Manual (Page 113)

Figure 6-4. BESTlogic Function Element Screen, Breaker Status
Current breaker status can be read from HMI Screen 1.5.6 and through the communication ports using
the RG-STAT command. The General Status Reporting subsection provides more information about this
command.
The number of breaker operations can be read at HMI Screen 4.3.1. The counter value can be adjusted
using the Edit key. This allows the relay counter value to be matched to an existing mechanical
cyclometer on a breaker mechanism. Write access to the reports functions must be gained to edit this
value at the HMI. Breaker operations can be read or set through the communication ports using the RB-
OPCNTR (report breaker, operations counter) command.
The breaker operations counter can be monitored to give an alarm when the value exceeds a threshold.
See Breaker Alarms in this section for more information about this feature.
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. Figure 6-8
illustrates breaker status during a fault and protective trip. Table 6-8 serves as a legend for the call-outs of
Figure 6-8.
Every 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 squared
in primary amperes. 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 relay will
use for 100 percent duty (Dmax). 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.
If the breaker monitoring mode is set to sum I (not I 2 ), the relay sums the sum of the currents that are
interrupted and will set the breaker duty alarm when the sum passes that breaker duty setting (Dmax).
The approach to set Dmax is to select the maximum number of operations at some current level and
enter a Dmax calculated by the equation:
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