ABB Relion 650 Series Commissioning Manual page 104

Section 7
Glossary
96
provides packet routing, fragmentation and re-assembly
through the data link layer.
2. Ingression protection according to IEC standard
IP 20 Ingression protection, according to IEC standard, level 20
IP 40 Ingression protection, according to IEC standard, level 40
IP 54 Ingression protection, according to IEC standard, level 54
IRF Internal fail signal
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
LDD Local detection device
LED Light emitting diode
MCB Miniature circuit breaker
MCM Mezzanine carrier module
MVB Multifunction vehicle bus. Standardized serial bus originally
developed for use in trains.
NCC National Control Centre
OCO cycle Open-close-open cycle
OCP Overcurrent protection
OLTC On load tap changer
OV Over voltage
Overreach A term used to describe how the relay behaves during a fault
condition. For example a distance relay is over-reaching
when the impedance presented to it is smaller than the
apparent impedance to the fault applied to the balance point,
i.e. 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
PCM600 Protection and control IED manager
PC-MIP Mezzanine card standard
PISA Process interface for sensors & actuators
PMC PCI Mezzanine card
POTT Permissive overreach transfer trip
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Commissioning Manual