IRIG-B:
InterRange Instrumentation Group Time code format B,
standard 200
ITU
International Telecommunications Union
LAN
Local area network
LIB 520
High-voltage software module
LCD
Liquid crystal display
LDCM
Line data communication module
LDD
Local detection device
LED
Light-emitting diode
LNT
LON network tool
LON
Local operating network
MCB
Miniature circuit breaker
MCM
Mezzanine carrier module
MPM
Main processing module
MVAL
Value of measurement
MVB
Multifunction vehicle bus. Standardized serial bus originally
developed for use in trains.
NCC
National Control Centre
NOF
Number of grid faults
NUM
Numerical module
OCO cycle
Open-close-open cycle
OCP
Overcurrent protection
OLTC
On-load tap changer
OTEV
Disturbance data recording initiated by other event than start/
pick-up
OV
Overvoltage
Overreach
A term used to describe how the relay behaves during a fault
condition. For example, a distance relay is overreaching when
the impedance presented to it is smaller than the apparent
impedance to the fault applied to the balance point, that is, the
set reach. The relay “sees” the fault but perhaps it should not
have seen it.
PCI
Peripheral component interconnect, a local data bus
PCM
Pulse code modulation
Section 5
1MRK 511 413-UUS B
Glossary
56
650 series 2.2 ANSI
Communication protocol manual