38
Optimizer3 will detect fugitive emission (leaks) of SF₆ far earlier than the 63X pressure switch or SF₆ controller. Leaks are not only
detected, but the day on which the low-gas alarm will assert is determined and made known to the maintenance planner. Beyond
this, Optimizer3 calculates how much SF₆ has leaked and when the circuit breaker is re-filled and with how much SF₆ gas. Circuit
breakers that have had leak problems over their life are likely to also have high moisture content in the SF₆ gas. These circuit
breakers are good candidates for SF₆ Dew Point monitoring with an added OM-DPS sensor.
Optimizer3 monitors the phase currents and calculates the I²T during the arcing portion of the circuit interruption. I²T is an
abbreviation for
∫
I²T dt from contact part until the time when the arc is extinguished. This is done for each phase separately. By
keeping track of the cumulative duty for each pole separately, a pole replacement might be justified in certain circumstances
compared with a full circuit breaker replacement, thereby reducing O&M expense.
OPERATING MODES
The Optimizer3 has five pairs of control inputs which are connected to specific combinations of open coils, close coils, auxiliary
switches, red light bulbs, green light bulbs, and other control circuit inputs as appropriate for a circuit breaker. The DC voltage
levels (states) of these circuit nodes and their transitions are interpreted by the Optimizer3 to produce operating times, main
contact state (OPEN/CLOSE), and other parameters.
NOTE
: The Optimizer3 is limited to 20 mS minimum time between successive OPEN - CLOSE or CLOSE - OPEN operations.
Operations that occur more rapidly than this might not be recorded.
Figure 43
– Circuit Breaker Monitoring-Input Modes
NOTE
: AD represents “A Input Delay” the time skew between the control signal that begins the monitor recording (usually the
assertion of the 52a auxiliary switch), and main breaker contact parting.
The only reference to breaker main contact parting is to the 52a auxiliary switch. It is very important to accurately know the time
difference between 52a assertion and the main contact parting on an OPEN breaker operation. The quality of the arcing time and
I²T calculation of main contact duty depends on the accuracy of this parameter.