GE EPM 5200, EPM 5300, EPM 5350 instruction manual Waveform and Harmonics, Sin ω ⋅ t

WAVEFORM AND HARMONICS CHAPTER 1: AC POWER MEASUREMENT

1.4Waveform 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.

SINUSOIDAL WAVEFORM:

DISTORTED WAVEFORM:

A • sin (ω ⋅ t)

A • sin(ω • t) + A1 • sin(ω1 • t) + A2 • sin(ω2 • t) + A3 • sin(ω3 • t) + L

TOTAL HARMONIC DISTORTION (THD):

% of THD =	RMS of Total Harmonic Distortion Signal	⋅ 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.

FIGURE 1–5: % THD GRAPH

1–6 EPM 5300 SERIES ADVANCED POWER METERS – INSTRUCTION MANUAL