P.9.24
SEL-411L Relay Protection Manual Date Code 20151029
Monitoring and Metering
Station DC Battery System Monitor
If the ground detection factor ratio exceeds a setting threshold, the relay
asserts the DCIG Relay Word bit. To set the ground detection factor threshold,
enable the advanced Global settings (set EGADVS := Y), and set the DC1GF
and the DC2GF thresholds at a value close to 1.05 (the factory default setting)
to allow for some slight battery system unbalance of around 5 percent.
Table 9.11 lists the ground detection factor threshold settings for this example.
DC Battery Monitor Alarm
You can use the battery monitor Relay Word bits to alert operators for
out-of-tolerance conditions in the battery systems. Add the appropriate Relay
Word bit to the SEL
OGIC control equation that drives the relay control output
you have selected for alarms. For example, use the b contact of control output
OUT214. Set the SEL
OGIC control equation to include the battery monitor
thresholds.
OUT214 := NOT (HALARM OR SALARM OR DC1F OR DC1W OR DC1R OR DC1G)
(Output SELOGIC Equation)
This is one method; you can implement many other methods as well.
DC Battery Monitor
Metering
The relay monitors battery system voltages and records time stamps for
voltage excursions. In addition, the relay records maximum and minimum
battery voltages. Figure 9.14 shows a sample dc battery monitor meter report.
Use the MET BAT command from a communications terminal to obtain this
report.
=>MET BAT <Enter>
Relay 1 Date: 03/22/2001 Time: 09:37:10.035
Station A Serial Number: 2001001234
Station Battery VDC VDCPO VDCNE VAC
VDC1 (V) 24.17 11.98 -12.19 0.01
VDC2 (V) 47.68 23.80 -23.88 0.02
VDC1(V) Date Time VDC2(V) Date Time
Minimum 20.12 03/15/2001 14:28:59.172 41.64 03/22/2001 08:46:25.726
Enter L-Zone 03/15/2001 14:28:51.490 03/18/2001 18:46:23.868
Exit L-Zone 03/15/2001 14:29:05.035 03/18/2001 18:47:55.441
Maximum 27.19 03/19/2001 08:34:49.761 50.84 03/22/2001 08:34:55.490
Enter H-Zone 03/19/2001 08:34:27.172 03/22/2001 08:34:27.172
Exit H-Zone 03/19/2001 08:37:01.041 03/22/2001 08:35:00.912
LAST DC RESET: 03/15/2001 12:30:30.492
=>
Figure 9.14 Battery Metering: Terminal
Any battery voltage between setting DCnLWP and the dc battery monitor low
limit of 15 Vdc is in the L-Zone. Battery voltages in the H-Zone are voltages
higher than the DCnHWP setting.
Reset DC Battery Monitor Metering
Use the MET RBM command from a communications terminal to reset the dc
battery monitor. You can also reset the dc battery monitor with Global
SEL
OGIC setting RST_BAT when EDRSTC (Data Reset Control) is Y.
Table 9.11 Example DC Battery Monitor Settings—Ground Detection Factor
(EGADVS := Y)
Setting Description Indication Value
DC1GF Ground detection factor, Mon. 1 Battery wiring ground(s) 1.05
DC2GF Ground detection factor, Mon. 2 Battery wiring ground(s) 1.05
NOTE: Only the upper ground
detection factor in Figure 9.12 is
entered as a setting. The relay
calculates the lower factor by taking
the reciprocal of the upper factor:
1/1.05 = 0.952 in this case.
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