Sel SEL-421 - Page 288

GL.2
SEL-421/SEL-421-1 Relay Date Code 20020501
Glossary
Access Level O—Anti-Aliasing Filter
Access Level O
A relay command level you use to access all Access Level 1 and Access Level
B (Breaker) functions plus Output, Global, Front Panel, Report, Port, and
DNP settings.
Access Level P
A relay command level you use to access all Access Level 1 and Access Level
B (Breaker) functions plus Protection, SEL
OGIC, Global, Group, Breaker
Monitor, Front Panel, Report, Port, and DNP settings.
ACSELERATOR
®
A Windows
®
-based program that simplifies settings and provides analysis
support.
Active Settings Group
The settings group that the SEL-421 Relay is presently using from among six
settings groups available in the relay.
Admittance
The reciprocal of impedance; I/V.
Advanced Settings
Settings for customizing protection functions; these settings are hidden unless
you set EADVS := Y and EGADVS := Y.
Alias
An alternate name for a Relay Word bit used in the SEL-421 Relay Sequential
Events Recorder (SER) function. The assigned alias appears in the SER report
in place of the Relay Word bit, making the SER report easier to review.
Analog Quantities
Variables represented by such fluctuating measurable quantities as
temperature, frequency, current, and voltage.
AND Operator
Logical AND. An operator in Boolean SELOGIC control equations that
requires fulfillment of conditions on both sides of the operator before the
equation is true.
ANSI Standard
Device Numbers
A list of standard numbers used to represent electrical protection and control
relays. The standard device numbers used in this instruction manual include
the following:
25 Synchronism-check element
27 Undervoltage Element
32 Directional Elements
50 Overcurrent Element
51 Inverse Time-Overcurrent Element
52 AC Circuit Breaker
59 Overvoltage Element
67 Definite Time Overcurrent
79 Recloser
86 Breaker Failure Lockout
89 Disconnect
These numbers are frequently used within a suffix letter to further designate
their application. The suffix letters used in this instruction manual include the
following:
P Phase Element
G Residual/Ground Element
N Neutral/Ground Element
Q Negative-Sequence (3I2) Element
Anti-Aliasing Filter
A low pass filter that blocks frequencies too high for the given sampling rate
to accurately reproduce.