Novatech Bitronics M87X Series, Руководство пользователя

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ML0021 August 15, 2018
42
Copyright 2018 Bitronics, LLC
(which is the denominator), and the result will be the actual RMS magnitude of the
selected harmonic.
Fundamental Volts and Amps can be used in conjunction to obtain Fundamental VAs, and
when used with Displacement Power Factor can yield Fundamental Watts and
Fundamental VARs.
4.8.6 Fundamental Watts / Volt-Amperes (VAs) / VARs (1-Cycle Update)
Fundamental Watt, VAR, and VA Demands are calculated analogous to the True Watts /
Volt-Amperes (VAs) / VARs of Section 4.4, but contain only information about the
fundamental. The Fundamental Total VA calculation type is the same as the True Total
VA calculation type (Section 4.4)
4.8.7 K-Factor (1-Cycle Update)
K-Factor is a measure of the heating effects on
transformers, and it is defined in ANSI/IEEE C57.110-
1986. Equation 4 is used by the M87x to determine K-
Factor, where "h" is the harmonic number and "I
h
" is the
magnitude of the h
th
harmonic. K-Factor is measured on
each of the three phases of amps, however there is no
"Total" K-Factor. K-Factor, like THD and PF, does not
indicate the actual load on a device, since all three of these
measurements are ratios. Given the same harmonic ratio, the calculated K-Factor for a
lightly loaded transformer will be the same as the calculated K-Factor for a heavily loaded
transformer, although the actual heating on the transformer will be significantly different.
4.8.8 Displacement Power Factor (1-Cycle Update)
Displacement Power Factor is defined as the cosine of the angle (phi) between the
Fundamental Voltage Vector and the Fundamental Current Vector. The sign convention
for Displacement Power Factor is the same as for Power Factor, shown in Figure 7 (pg.
33).
The Total Displacement Power Factor measurement is calculated using the "Power
Triangle,” or the three-phase Fundamental WATTS divided by the three-phase
Fundamental VAs. The per-phase Fundamental VA measurement is calculated from the
product of the per-phase Fundamental Amp and Fundamental Volts values. The three-
phase Fundamental VA measurement is the sum of the per-phase Fundamental VA values
(Arithmetic VAs).
4.8.9 Phase Angle (1-Cycle Update)
The Phase Angle is calculated for the Bus 1 to Bus 2 per-phase Fundamental Voltages
and Fundamental Voltage to Fundamental Current. It is the Bus 1 Fundamental Voltage
angle minus either the Bus 1 Fundamental Current or Bus 2 Fundamental Voltage angle
for a given phase. Values are from -180 to +180 Degrees.
63
2 2
1
63
2
1
100%
h
h
h
h
I h
K Factor
I



  


Equation 4 - K-Factor