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PRESSURE/DENSITY TREND, FORECAST PLANNING ALARMS
If an SF₆ leak is detected in any of the SF₆ zones and it exceeds the Pressure/Density Trend Alarm Limit, the alarm relay can be
asserted, if desired. The alarm status is available as a DNP SCADA point.
LOW GAS ALARM FORECAST & FORECAST PLANNING ALARM
The Low Gas Alarm Forecast reports how many days until the Density/Pressure Danger Alarm will be reached. Based on this SF₆
leak trend, the number of days until this alarm is asserted is given on the Sensors Page and available via DNP.
The maximum Forecast Planning Alarm limit is 180 days:
The Forecast Planning Alarm adds a user-defined number of days to the Low Gas Alarm Forecast to allow for planning, equipment
preparation, and outage scheduling. When the SF₆ gas pressure decreases so that the predicted number of days until the Danger
Alarm is asserted is equal to or less than the Forecast Planning Alarm, the alarm relay can be asserted, if desired. The alarm status
and the forecast value are available as DNP SCADA points.
The Pressure/Density Trend status is shown on the Sensors Page:
Forecast status is shown on the Sensors Page:
To clear the low-gas alarm:
1. Add SF₆ to a value greater than 5% over the alarm limit that is set, then…
2. Manually clear the alarm from the Action Page
Figure 31
– Clearing Low Gas Alarms