Table of Contents
Advertisement
CHAPTER 1: AC POWER MEASUREMENT
1.4: Waveform and Harmonics
Ideal power distribution has sinusoidal waveforms on voltages and currents. In real-life applications,
where inverters, computers, and motor controls are used, distorted waveforms are generated. These
distortions consist of harmonics of the fundamental frequency.
ω
⋅
A
•
sin
(
t)
SINUSOIDAL WAVEFORM:
ω
ω
ω
ω
DISTORTED WAVEFORM:
A
•
sin(
•
t)
+
A
•
sin(
•
t)
+
A
•
sin(
•
t)
+
A
•
sin(
•
t)
+
L
1
1
2
2
3
3
TOTAL HARMONIC DISTORTION (THD):
RMS
of
Total
Harmonic
Distortion
Signal
×
%
of
THD
=
100
RMS
of
the
Fundamenta
l
Signal
HARMONIC DISTORTION: A destructive force in power distribution systems. It creates safety problems,
shortens the life span of distribution transformers, and interferes with the operation of electronic devices.
The Futura+ monitors the harmonic distortion to the 31st harmonic. A waveform capture of distorted
waveform is also available.
% THD GRAPH
4
EPM 5000 series Advanced Power Meters
GE Multilin
- Quick Links:
- Instruction Manual
- Three-Phase System
Hide quick links:
Advertisement
Table of Contents
