Thd Push Button: Power Quality Measurements; Thd: Total Harmonic Distortion - AEMC 721 User Manual

Clamp-on harmonic meter

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5.3

THD Push Button: Power Quality Measurements

THD gives access to Power Quality measurements (%THD, %DF, and CF)

and can be accessed while in Current or in Voltage.

The THD push button accesses three measurement values by sequen-

tially pressing the button:

%THD is the Total Harmonic Distortion and referenced to the Fundamental

(50/60 Hz) signal. The THD is expressed

as a percentage and may be greater in

amplitude than the fundamental. A read-

ing greater than 100% is possible. The

%THD is also referred to as the Har-

monic Factor or %THD-F.

Mathematically, the Total Harmonic Dis-

tortion, or %THD, is the ratio of the root-

mean-square (RMS) of the harmonic

content to the root-mean-square (RMS)

value of the fundamental, and expressed

as a percentage (see p. 16 for details).

Harmonic Meter Model 721

Push Button Sequencing:

A or V → %THD → %DF → CF → A or V

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