ABB REC650 Commissioning Manual page 112

Section 9
Glossary
104
I-GIS Intelligent gas-insulated switchgear
Instance When several occurrences of the same function are available
in the IED, they are referred to as instances of that function.
One instance of a function is identical to another of the same
kind but has a different number in the IED user interfaces.
The word "instance" is sometimes defined as an item of
information that is representative of a type. In the same way
an instance of a function in the IED is representative of a
type of function.
IP 1. Internet protocol. The network layer for the TCP/IP
protocol suite widely used on Ethernet networks. IP is a
connectionless, best-effort packet-switching protocol. It
provides packet routing, fragmentation and reassembly
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 failure 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 overreaching
when the impedance presented to it is smaller than the
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Commissioning Manual