Date Code 20020129
Metering and Monitoring
5-9
SEL-387E Instruction Manual
If the prompt is confirmed, the relay resets all energy values and records the date, otherwise the
relay responds with the command aborted message.
S
TATION
DC B
ATTERY
M
ONITOR
Use the station dc battery monitor in the SEL-387E Relay to alarm for undervoltage and
overvoltage dc battery conditions and to view how station dc battery voltage fluctuates during
tripping, closing, and other dc control functions. The monitor measures station dc battery
voltage applied to the rear-panel terminals labeled Z25 (+) and Z26 (–). Access the station dc
battery monitor settings (DC1P, DC2P, DC3P, and DC4P) with the
SET G
command.
Instantaneous Battery Voltage Values
The
MET
serial port command provides instantaneous values of the station dc battery voltage
(Vdc). To obtain these values from the relay front panel, press the METER pushbutton, use the
arrow pushbuttons to highlight VDC, and then press the SELECT pushbutton.
Undervoltage and Overvoltage Alarms
The flexibility of SEL
OGIC
®
control equations lets you create battery warning and failure alarms
that trigger when the station dc battery voltage falls below or exceeds voltage thresholds. Figure
5.2 shows the alarm logic and how Relay Word bits DC1 to DC4 can be used with DC1P, DC2P,
DC3P, and DC4P threshold settings to create the alarms. Figure 5.3 shows the warning and
alarm regions.
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B
B
B
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Figure 5.2: Station DC Battery Monitor Alarm Logic