ABB Relion RES670, Applications Manual

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RISC Reduced instruction set computer
RMS value Root mean square value
RS422 A balanced serial interface for the transmission of digital
data in point-to-point connections
RS485 Serial link according to EIA standard RS485
RTC Real-time clock
RTU Remote terminal unit
SA Substation Automation
SBO Select-before-operate
SC Switch or push button to close
SCL Short circuit location
SCS Station control system
SCADA Supervision, control and data acquisition
SCT System configuration tool according to standard IEC
61850
SDU Service data unit
SELV circuit Safety Extra-Low Voltage circuit type according to
IEC60255-27
SFP Small form-factor pluggable (abbreviation)
Optical Ethernet port (explanation)
SLM Serial communication module.
SMA connector Subminiature version A, A threaded connector with
constant impedance.
SMT Signal matrix tool within PCM600
SMS Station monitoring system
SNTP Simple network time protocol – is used to synchronize
computer clocks on local area networks. This reduces the
requirement to have accurate hardware clocks in every
embedded system in a network. Each embedded node can
instead synchronize with a remote clock, providing the
required accuracy.
SOF Status of fault
SPA Strömberg Protection Acquisition (SPA), a serial master/
slave protocol for point-to-point and ring communication.
SRY Switch for CB ready condition
ST Switch or push button to trip
Starpoint Neutral point of transformer or generator
1MRK 511 407-UEN C
Section 24
Glossary
Phasor measurement unit RES670 2.2 IEC 371
Application manual