Siemens SIPROTEC 7SS523 V3.2 Manual page 420

Appendix
A.20 Abbreviations
404
AB Auxiliary bus (bus coupler) sections (sections which serve exclusively for longi-
tudinal connection of bus zones and to which no outgoing feeders are connect-
ed)
BB Busbar protection
BF Breaker Failure
BI Binary input
BO Binary output
BSZ1 Processing board for protection in the check zone
BSZ2/3 Processing boards for protection in the selective zones
BU Bay unit
BZ Bus zone
CB Circuit Breaker
CBF Breaker failure protection
CFC Continuous Function Chart
CU Central unit
CZ Check zone
DA Direct address
EAZ Input/output module
g.a. group alarm
HW Hardware
ISOL Isolator
KOM Communication board used for operation
LED Light emitting diode
M Measurement
MLFB Coded ordering numbers
PC Personal computer
REL Relay
RTC Real Time Clock
SBK Control-operation-interface board
SK Serial link board
ZPS Central processor board of protection
7SS52 V4 Manual
C53000-G1176-C182-1