GL.3
Date Code 20130214 Instruction Manual SEL-2414 Transformer Monitor
Glossary
MAC Address—SELOGIC Control Equation
MAC Address
The Media Access Control (hardware) address of a device connected to a shared
network medium, most often used with Ethernet networks.
NEMA
Abbreviation for National Electrical Manufacturers Association.
Nominal Frequency
Normal electrical system frequency, usually 50 or 60 Hz.
Phase Rotation
The sequence of voltage or current phasors in a multiphase electrical system. In
an ABC phase rotation system, the B-phase voltage lags the A-phase voltage by
120 degrees and the C-phase voltage lags B-phase voltage by 120 degrees. In an
ACB phase rotation system, the C-phase voltage lags the A-phase voltage
by120 degrees and the B-phase voltage lags the C-phase voltage by 120 degrees.
Pickup Time
The time measured from the application of an input signal until the output signal
asserts. The time can be settable, as in the case of a logic variable timer, or can be
a result of the characteristics of an element algorithm, as in the case of an over-
current element pickup time.
Power, P
Real part of the complex power (S) expressed in units of Watts (W), kilovolt-
watts (kW), or megawatts (MW).
Power Factor
The cosine of the angle by which phase current lags phase voltage in an ac elec-
trical circuit. Power factor equals 1.0 for power flowing to a resistive load.
PT
Abbreviation for potential transformer. Also referred to as a voltage transformer
or VT.
RAM
Abbreviation for Random Access Memory. Volatile memory where the device
stores intermediate calculation results, Device Word bits, and other data that are
updated every processing interval.
Power, Q
Reactive part of the complex power (S) expressed in units of Vars (Var), kilovars
(kVar), or megavars (MVar).
Remote Bit
A Device Word bit for which state is controlled by serial port commands, includ-
ing the CONTROL command, binary Fast Operate command, or Modbus
®
RTU,
Modbus TCP, DNP3, or DNP3 LAN/WAN command.
ROM
Abbreviation for Read-Only Memory. Nonvolatile memory where the device
firmware is stored.
RTD
Abbreviation for Resistance Temperature Device. An RTD is made of a metal
having a precisely known resistance and temperature coefficient of resistance.
The SEL-2414 (and the SEL-2600 Device RTD Modules) can measure the
resistance of the RTD, and thus, determine the temperature at the RTD location.
Typically embedded in the motor windings or attached to the races of bearings.
Self-Test
A function that verifies the correct operation of a critical device subsystem and
indicates if an out-of-tolerance condition is detected. The SEL-2414 is equipped
with self-tests that validate the device power supply, microprocessor, memory,
and other critical systems.
SELOGIC
Control Equation
A device setting that allows you to control a device function (such as an output
contact) by using a logical combination of device element outputs and fixed logic
outputs. Logical AND, OR, INVERT, rising edge [/], and falling edge [\] opera-
tors, plus a single level of parentheses are available to use in each control equa-
tion setting.
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