6-16 BE1-951 Reporting and Alarm Functions 9328900990 Rev L
RB-OPCNTR Command
Purpose: Read/Set breaker operations counter.
Syntax: RB-OPCNTR=<#operations>
Comments: #operations = number of breaker operations recorded (0-99,999). If the counter exceeds
99,999, the counter will wrap back to 0.
RB-OPCNTR Command Examples:
Example 1. Read the number of breaker operations.
>RB-OPCNTR
14
Example 2. Synchronize the relay breaker operations counter with an external counter reading of 65
operations.
>RB-OPCNTR=65
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 operations can also be read using the RB command. The RB command returns the number of
breaker operations and breaker contact duty information.
RB Command
Purpose: Read breaker status.
Syntax: RB
Comments: No password access is required to read settings.
RB Command Example:
Example 1. Use the RB command to obtain breaker information.
>RB
RB-DUTYA=92.04; RB-DUTYB=22.25; RB-DUTYC=27.87
RB-OPCNTR=65
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 (SB-LOGIC).
Figure 6-6 illustrates breaker status (SB-LOGIC) during a fault and protective trip. Table 6-8 serves as a
legend for the call-outs of
Figure 6-6.
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 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 (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.
If the breaker monitoring mode is set to sum I, 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 (D
MAX
). The approach
to set DMAX is to select the maximum number of operations at some current level and enter D
MAX
calculated by the equation:
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