Measurement Computing WavePort 312P rev.1.0 - Manual (Page 79)

Glossary
PowerVista User’s Manual Glossary 11-3
K-Factor
A component of the ANSI Standard C57.110-1986 transformer derating equation, and more commonly used to
classify the harmonic carrying capability of a transformer. This factor is not explicitly described in C57.110 but
is the main component used in the derating equation. The K-Factor is not a derating factor, but is used in the
derating equation. Be careful not to confuse K-Factor with the constant K on page 11 of C57.110. All currents
are in per unit.
H
∑
∑ ∑ ∑ Ipu
h
2 h 2
h=1
K-Fact =
____________
H
∑
∑ ∑ ∑ Ipu
h
2
h=1
Line Voltage Notch
The dip in the supply voltage to a converter due to the momentary short-circuit of the ac lines during a
commutation interval. Alternatively, the momentary dip in supply voltage caused by the reactive drops in the
supply circuit during the high rates of change in currents occurring in the ac lines during commutation.
Non-Characteristic Harmonic
Harmonics that are not produced by semiconductor converter equipment in the course of normal operation.
These may be a result of beat frequencies; a demodulation of characteristic harmonics and the fundamental; or
an imbalance in the ac power system, asymmetrical delay angle, or cycloconverter operation.
Non-Linear Load
A load that draws a non-sinusoidal current wave when supplied by a sinusoidal voltage source.
Point of Common Coupling (PCC)
Is defined by this direct quote from IEEE Standard 519-1992,
"The recommendation described in this document attempts to reduce the harmonic effects at any point in the
entire system by establishing limits on certain harmonic indices (currents and voltages) at the point of common
coupling (PCC), a point of metering, or any point as long as both the utility and the consumer can either access
the point for direct measurement of the harmonic indices meaningful to both or can estimate the harmonic
indices at point of interference (POI) through mutually agreeable methods. Within an industrial plant, the PCC
is the point between the non-linear load and other loads."
Pulse Number
The total number of successive non-simultaneous commutations occurring within a converter circuit during each
cycle when operating without phase control. It is also equal to the order of the principal harmonic in the direct
voltage, that is, the number of pulses present in the dc output voltage in one cycle of the supply voltage.