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IM WT310E-01EN

Features

App

Index

1.6 Harmonic Measurement (Option)

Usingharmonicmeasurement,youcanmeasurevoltage,current,andactivepoweruptothe50th

harmonic; the harmonic distortion factor for each harmonic order; and the phase angle of each

harmonic order with respect to the fundamental wave (1st harmonic). You can also compute the

total rms values (fundamental wave + harmonics) for voltage, current, and active power and the total

harmonic distortion (THD).

For a list of the symbols for the measurement functions that can be measured with harmonic

measurement and their descriptions, see “Harmonic Measurement Functions” under “Items That This

Instrument Can Measure.”

PLL Source (For procedures, see section 6.3)

For harmonics to be measured, the fundamental period (the period of the fundamental signal) that will

be used to analyze the harmonics must be determined. The signal for determining the fundamental

period is the PLL (phase locked loop) source. For stable harmonic measurement, use an input signal

with low distortion and few fluctuations as the PLL source.

For explanations of the terms fundamental wave, harmonics, harmonic orders, and other terms, see

appendix 2.

Measured Harmonic Order (For procedures, see section 6.3)

Youcansettheupperlimitofmeasuredharmonicorderintherangeof2to50.However,therange

varies depending on the fundamental (1st harmonic) frequency. This is because the upper limit of

harmonicsthatarecomputedvariesdependingonthefundamentalfrequency.Thedefaultvalueis50.

Total Harmonic Distortion Equation (For procedures, see section

6.3)

You can select the equation for determining the total harmonic distortion from the options listed below.

Thefollowingexplanationsareforwhentheupperlimitofmeasuredharmonicorderis50.Ifthe

maximumnumberofmeasuredharmonicordersislessthan50,theequationwillbeappliedtothe

harmonic orders up to the specified maximum number.

• IEC:Theratioofthermsvalueofharmonics2to50tothermsvalueofthefundamentalwave(1st

harmonic) is calculated.

• CSA:Theratioofthermsvalueofharmonics2to50tothermsvalueofharmonics1to50is

calculated.

YOKOGAWA WT310EH User Manual

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