![Schweitzer Engineering Laboratories SEL-421-4 Instruction Manual Download Page 1059](http://html.mh-extra.com/html/schweitzer-engineering-laboratories/sel-421-4/sel-421-4_instruction-manual_12167261059.webp)
8.21
Date Code 20171006
Instruction Manual
SEL-400 Series Relays
Monitoring
Station DC Battery System Monitor
Definitions for the items and fields in the Compressed ASCII configuration are
the following:
➤
yyyy is the checksum
➤
iii is an integer value
➤
fff is a floating-point value
The relay reports the data as A-Phase in the first line, B-Phase in the second line,
and C-Phase in the third line. Pole scatter data are slightly different: TAB is in the
first line, TBC is in the second line, and TCA is in the third line.
Station DC Battery System Monitor
NOTE:
This section lists settings for
Station DC Battery Monitor 1; settings
for Station DC Battery Monitor 2 are
similar; replace 1 in the setting with 2.
The relay automatically monitors station battery system health by measuring the
dc voltage, ac ripple, and voltage between each battery terminal and ground.
SEL-400 series relays provide either one or two dc monitor channels. See the
product-specific instruction manual to see how many breaker monitor channels
the relay supports. Four voltage thresholds give you the ability to create five sens-
ing zones (low failure, low warning, normal, high warning, and high failure) for
the dc voltage.
The ac ripple quantity indicates battery charger health. When configuring the ac
ripple setting DC1RP, we can define the ripple content of a dc supply as the peak-
to-peak ac component of the output supply waveform.
The relay also makes measurements between the battery terminal voltages and
station ground to detect positive and negative dc ground faults.
shows
a typical dual-battery dc system.
Figure 8.12
Typical Station DC Battery System
Station
Service
Chassis
Ground
Power
Battery
Charger
125 Vdc
Relay
Comm.
Equipment
+
–
Vdc 1
–
+
Vdc 2
–
+
Battery
Charger
48 Vdc
Power
+
–
Summary of Contents for SEL-421-4
Page 6: ...This page intentionally left blank ...
Page 14: ...This page intentionally left blank ...
Page 30: ...This page intentionally left blank ...
Page 104: ...This page intentionally left blank ...
Page 128: ...This page intentionally left blank ...
Page 536: ...This page intentionally left blank ...
Page 584: ...This page intentionally left blank ...
Page 616: ...This page intentionally left blank ...
Page 696: ...This page intentionally left blank ...
Page 750: ...This page intentionally left blank ...
Page 755: ...Instruction Manual PM400 01 NB SEL 400 Series Relays Instruction Manual 20171006 ...
Page 776: ...This page intentionally left blank ...
Page 932: ...This page intentionally left blank ...
Page 976: ...This page intentionally left blank ...
Page 1024: ...This page intentionally left blank ...
Page 1038: ...This page intentionally left blank ...
Page 1064: ...This page intentionally left blank ...
Page 1128: ...This page intentionally left blank ...
Page 1206: ...This page intentionally left blank ...
Page 1316: ...This page intentionally left blank ...
Page 1350: ...This page intentionally left blank ...
Page 1464: ...This page intentionally left blank ...
Page 1468: ...This page intentionally left blank ...
Page 1492: ...This page intentionally left blank ...
Page 1518: ...This page intentionally left blank ...