Date Code 20020903 SEL-587Z Relay
Glossary
“a” Contact
A breaker auxiliary contact (ANSI Standard Device Number 52A) that closes
when the breaker is closed and opens when the breaker is open.
“a” Output
A relay control output that closes when the output relay asserts.
“b” Contact
A breaker auxiliary contact (ANSI Standard Device Number 52B) that opens
when the breaker is closed and closes when the breaker is open.
“b” Output
A relay control output that opens when the output relay asserts.
3U, 4U, 5U
The designation of the vertical height of a device in rack units. One rack unit,
U, is approximately 1.75 inches or 44.45 mm.
A
Abbreviation for amps or amperes; unit of electrical current flow.
Acceptance Testing
Testing that confirms that the relay meets published critical performance
specifications and requirements of the intended application. Such testing
involves testing protection elements and logic functions when qualifying a
relay model for use on the utility system.
Access Level
A relay command level with a specified set of relay information and
commands. Except for Access Level 0, you must have the correct password to
enter an access level.
Access Level 0
The least secure and most limited access level. No password protects this
level. From this level, you must enter a password to go to a higher level.
Access Level 1
A relay command level you use to monitor (view) relay information. The
default access level for the relay front panel.
Access Level 2
The most secure access level where you have total relay functionality and
control of all settings types.
Admittance
The reciprocal of impedance; I/V.
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. Represented by * symbol.
ANSI Standard
Device Numbers
A list of standard numbers used to represent electrical protection and control
relays. Standard device numbers 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
To Next Page
Loading...
