Measurement Computing WavePort 312P rev.1.0 - Manual (Page 78)

Glossary
11-2 Glossary PowerVista/312 User’s Manual
Fourier Transform
The continuous Form of the Fourier Series is shown below in equation form.
∞ ∞ ∞ ∞
X( ω ω ω ω) = ⌠ ⌠ ⌠ ⌠ [ x(t)e -jω ω ω ωt ]dt
⌡ ⌡ ⌡ ⌡ -∞ ∞ ∞ ∞
This equation shows that as a time wave is multiplied by another sinusoidal time wave at a given frequency, the
frequency component can be determined. For example, at a fixed frequency of say
ω = 377 (60 Hz), the
equation could be stated:
∞ ∞ ∞ ∞
X(377) = ⌠ ⌠ ⌠ ⌠ [ x(t)e -j377t
]dt
⌡ ⌡ ⌡ ⌡ -∞ ∞ ∞ ∞
Fundamental Frequency
The driving frequency of an electrical power system. In the U.S. the fundamental frequency of choice on the
major interconnected power grid is 60 Hz. Military systems often use a mix of 60 and 400 Hz base fundamental
frequency systems. These systems are not typically interconnected. Systems of different fundamental frequency
can be interconnected via frequency converters, DC links, and DC lines.
Harmonic
A frequency that is an integer multiple of a base fundamental frequency. For example, 300 Hz is the 5 th
harmonic of 60 Hz since it is 5 times 60 Hz.
Interruption
An interruption is a complete loss of supply voltage on one or more phases for an interval of time. Depending
on the time interval, interruptions can be grouped into three main categories:
Momentary: A duration up to 2 to 3 seconds.
Temporary: A duration from 2 to 3 seconds to about 1 minute.
Sustained: Any duration greater than 1 minute.
IT Product
IT Product is the inductive influence of currents on a telephone system expressed in terms of the product of a
currents root-mean-square magnitude (I), in amperes, times its telephone influence weighting factor (TIF).
Currents are in amps.
H
IT Product = ( ∑ ∑ ∑ ∑ [ I
H
•••• weighting factor ] 2
)
1/2
h=1