Siemens 7SA511 manual Glossary of Terms and Abbreviations, Abbreviations and Acronyms

7SA511 Line Protection Relay Introduction

This manual assumes you are using the relay’s operator panel to program, maintain, and operate the relay. If you are using DIGSI® software or some other application to control the relay, refer to the appropriate user guide when instructions in this manual are insufficient.

1.2 Glossary of Terms and Abbreviations

Following are definitions and descriptions of terms and abbreviations used in this manual that are unique to power systems and to Siemens relay technology in particular.

Abbreviations and Acronyms

A/D	analog-to-digital
AR	automatic reclose
CB	circuit breaker
C/O	changeover
CT	current transformer
CW	codeword
DAR	delayed automatic reclose
E	earth or ground
EEPROM	electrically erasable, programmable read only memory
E/F	earth (ground) fault
EPROM	erasable, programmable read only memory
FD	fault detection; fault detector
FNo	function number
I.T.	inverse time
LCD	liquid crystal display (on the relay operator panel)
LED	light emitting diode (on the relay operator panel)
LSA	a substation (Siemens’ Localized Substation Automation system)
m	memorized
M/C	manual close
mcb or m.c.b.	miniature circuit breaker
NC	normally closed
nm	not memorized
NO	normally open
O/C	overcurrent
PC	personal computer
pcb	printed circuit board
PCO	parameter changeover
PLC	power line carrier
POTT	permissive overreach transfer trip (pilot protection scheme)
PUTT	permissive underreach transfer trip (pilot protection scheme)
RAM	random access memory
RAR	rapid automatic reclose
ROM	read only memory
TT	transmit time
VT	voltage transformer

1-4 July 27, 1995