46
P.F. Q1 Q2 Q3 Q4
ANSI +
–
+
–
IEEE +
––
+
6.13 Power Factor Convention
Power Factor is the ratio of a signed number (true power) and an unsigned
number (apparent power). The VerifEye
®
meter allows users to select between
two conventions (ANSI and IEEE). In the IEEE convention, the PF sign follows the
sign of power itself. In the ANSI convention, a [+] PF indicates a lagging current
(inductive load), while a [–] PF indicates a leading current (capacitive load). The
sign relationships are shown below for these conventions in each
electrical quadrant.
6.14 Total Harmonic Distortion
The Verifeye
®
meter reports overall harmonic content in power (% T) based on its
measurement of Power, Var and Apparent Power as illustrated in the gure below.
This method only provides the overall harmonic content.
If the voltage is sinusoidial, the T measurement is a good estimate of both power
and current. However, if the voltage waveform is distorted, the reported T in power
can be misleading. The Power Meter Viewer Utilities software provides additional
analysis of harmonic content in voltage and current by sampling the raw data and
performing digital signal processing. Using this method, the individual harmonic
levels can be observed. The results are presented in a bar graph, as shown below.
Power Triangle
(for active loads)
Reactive Power
(KVAR)
Total Apparent Power (KVA)
THD
Displacement Apparent Power (dKVA)
Harmonic Apparent Power
Real Power
(KW)
Φ
6 COMMUNICATION AND VERIFICATION
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