Power Meter Bulletin No. 3020IM9503R6/98
Chapter 8—Metering Capabilities December 1998
62 1998 Square D All Rights Reserved
POWER ANALYSIS VALUES
The power meter provides power analysis values that can be used to detect
power quality problems, diagnose wiring problems, and more. Table 8-3
summarizes the power analysis values.
Table 8-3
Power Analysis Values
Value Reportable Range
THD-Voltage, Current (per phase) ➀ 0 to 3,276.7%
Fundamental Voltages (per phase) ➁
Magnitude 0 to 3,276,700 V
Angle 0.0 to 359.9°
Fundamental Currents (per phase) ➁
Magnitude 0 to 32,767 A
Angle 0.0 to 359.9°
THD—Total Harmonic Distortion (THD) is a quick measure of the total
distortion present in a waveform. It provides a general indication of the
“quality” of a waveform. Power meter models PM-620 and PM-650 use the
following equation to calculate THD:
thd—An alternate method for calculating Total Harmonic Distortion, used
widely in Europe. Power meter models PM-620 and PM-650 use the following
equation to calculate thd:
++
H
2
2
H
3
2
H
4
2
Total rms
+
x
100%
thd =
➀ PM-620 and PM-650.
➁ Via communications only.
++
H
2
2
H
3
2
H
4
2
+
x
100%
THD =
H
1