Hitachi Relion 670 Series Applications Manual page 350

Section 24
Glossary
PRP
PSM
PST
PTP
PT ratio
PUTT
RASC
RCA
RISC
RMS value
RS422
RS485
RTC
RTU
SA
SBO
SC
SCL
SCS
SCADA
SCT
SDU
SELV circuit
SFP
SLM
SMA connector
SMT
SMS
SNTP
SOF
SPA
SRY
ST
344
Parallel redundancy protocol
Power supply module
Parameter setting tool within PCM600
Precision time protocol
Potential transformer or voltage transformer ratio
Permissive underreach transfer trip
Synchrocheck relay, COMBIFLEX
Relay characteristic angle
Reduced instruction set computer
Root mean square value
A balanced serial interface for the transmission of digital data in point-to-point
connections
Serial link according to EIA standard RS485
Real-time clock
Remote terminal unit
Substation Automation
Select-before-operate
Switch or push button to close
Short circuit location
Station control system
Supervision, control and data acquisition
System configuration tool according to standard IEC 61850
Service data unit
Safety Extra-Low Voltage circuit type according to IEC60255-27
Small form-factor pluggable (abbreviation)
Optical Ethernet port (explanation)
Serial communication module.
Subminiature version A, A threaded connector with constant impedance.
Signal matrix tool within PCM600
Station monitoring system
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.
Status of fault
Strömberg Protection Acquisition (SPA), a serial master/slave protocol for point-
to-point and ring communication.
Switch for CB ready condition
Switch or push button to trip
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1MRK511407-UUS Rev. N
Phasor measurement unit RES670
Application manual