Page 276 - Electrical Engineering Dictionary
P. 276
direction of a fault, thus allowing the defect fault secure pertaining to a circuit, with
to be located. respect to a set of faults, if and only if for
any fault in this set, and any valid input code
fault kva fault kilovolt-amps (kva) is the the output is a non-code or correct code (the
fault level expressed in terms of volt-amps output is never an invalid code). The circuit
rather than amps. One advantage of using is considered to operate properly if the output
volt-amps rather than amps is that the same is a code word.
flow is experienced on both sides of a trans-
former when expressed in volt-amps, while fault simulation an empirical method
the flow changes due to the transformer turns used to determine how faults affect the op-
ratio when it is expressed in amps. Volt- eration of the circuit and how much testing is
amps for a three-phase fault are expressed required to obtain the desired fault coverage.
as 1.73 × rms line-line voltage × rms sym-
metrical fault current. Volt-amps for a single fault tolerance correct execution of a
phase fault are defined as 1.73 × rms line- specified function in a circuit (system), pro-
line voltage × rms symmetrical current in the vided by redundancy despite faults. The re-
faulted phase. dundancy provides the information needed to
negate the effects of faults.
fault latency the length of time between
the occurrence of a fault and the appearance fault tree the identification and analysis
of an error. of conditions and factors that cause or con-
tribute to the occurrence of a defined undesir-
fault masking a technique that hides the able event, usually one that significantly af-
effects of faults with the use of redundant fects system performance, economy, safety,
circuitry or information. or other required characteristics.
fault mva fault megavolt-amps (mva) is
fault-tolerant control system a system
thefaultlevelexpressedintermsofvolt-amps
that exhibits stability and acceptable perfor-
rather than amps. One advantage of using
mance in the presence of component faults
volt-amps rather than amps is the same flow
(failures) or large changes in the system that
is experienced on both sides of a transformer
resemble failures.
when expressed in volt-amps, while the flow
changes due to the transformer turns ratio
fax abbreviation for a machine that makes
when it is expressed in amps. Volt-amps for
and transmits facsimiles. See facsimile.
a three-phase fault are expressed as 1.73 ×
rmsline-linevoltage×rmssymmetricalfault
FCA See fixed channel assignment.
current. Volt-ampsforasinglephasefaultare
defined as 1.73 × rms line-line voltage× rms
FCM See fuzzy cognitive map or fuzzy
symmetrical current in the faulted phase.
c-means.
fault prevention any technique or process
that attempts to eliminate the possibility of FCT See field controlled thyristor.
having a failure occur in a hardware device
or software routine. FDD See frequency division duplex.
fault resistance the resistance that occurs FDDI See fiber distributed data interface.
at the point of fault due to voltage drop across
an arc or due to other resistance in the fault FDM Seefrequencydivisionmultiplexing.
path.
c
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